Thread: 500 hp/550 lb-ft from a 390?

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Hey guys great forum! This is my first post but I've perused all of the threads here so hopefully my questions won't be redundant....

Let me start off with the target numbers that I'd like to reach, application, then describe the pieces-parts I've got in hand and ultimately open the discussion for some advice and guidance.

Target: 500 hp/550 lb-ft of torque from a naturally aspirated 390 FE. Possible? Less would be acceptable but if ya don't ask......

Application: 1967 Mustang Coupe that will be a weekend toy and occasional cruise night ride. I'd also like to be able to be able to take a few shots at the 1/4 from time to time as well as play around in the twisties, too (the suspension and brakes will reflect this desire).

Here's what I've picked up along the way: A well seasoned (80,000 or so mile), standard bore (for now) C6ME-A Block with a 3U crankshaft, C6AE-C rods and a pair of C7AE-A heads. All of these supposedly came from the same engine and I'm inclined to believe the guy. They're also purported to be from a '67 Galaxie 2bbl and the 2V part is supported by the "2V 390" on the pistons. All of these parts will need to visit the machine shop since they've lived for an extended period of time (12+ years) in , and I quote the seller here..."a ratty old shed on my parents farm....". He wasn't lyin'.....A field mouse had actually taken up residence in the oil pan.....which was still bolted to the block...

In addition to the factory iron, I also have a 750 cfm vacuum secondary Holley that just showed up one day....Really, I have no idea where I got it or for what reason but I do know it's got next to no time on it so that's gonna be the carb...Actually, I think it was a trade for repairing a tube-type guitar amp for somebody but that's completely extraneous info.....sorry....

From my research here, it looks like the Erson setup or the Shelby setup is the ticket for rockers. I'm leaning towards the Erson's right now but I'm certainly open to suggestion. I've also pretty much settled on one of the Edelbrock aluminum intakes since I haven't found anything numbers wise to point me elsewhere. The Weiand looks to perform about the same but costs more. I'm still up for some input though, you guys have definitely got a handle on the FE stuff....

I want to stay with the 3U crank and factory rods if at all possible. I know, I know, "there ain't no substitute for cubic inches" but a major jump in displacement would necessitate a new crankshaft....Maybe for the next build....Regardless, I'll be boring the block .030 and maybe more? If that's the best balance between reliability and power so be it. I'm not certain just how much these blocks will take from this perspective. I've seen all sorts of recommendation but the majority of folks seem to think that .030 is the safest bet. I am kinda curious though, the C6ME-A casting appears to coincide with 3 different engines-the 390 (bore 4.05), the 410 (bore 4.05) and the 428 (bore 4.13). From what I can gather all of the 428 blocks have have "428" cast in the water jacket and that can be seen with the middle freeze plug removed. This block doesn't have the "428" nor did I expect it to but I am curious to know if it's advisable to take this casting to 4.13? The casting numbers are the same but are the blocks different in that all important area of cylider wall thickness? BTW, I base the previous information off of the information contained in the "High Performance Ford Engine Parts Interchange" book by George Reid.

Is it possible to get to the power levels that I've mentioned previously with those iron heads? If so, how much work would be involved in getting them to flow the necessary amount of air? If it's cost prohibitive, what are the thoughts on the aluminum ones available?

Will that crankshaft and rods stand up to the power levels that I'm trying to achieve? If not, what do I run?

Camshaft? I've got no idea at this point. It's gotta be streetable and not destroy the valvetrain in the process. Other than that, I'd love some input.

Recommendations on lifters, pushrods, pistons, rings, etc. eagerly solicited and gladly accepted.

I'll shut up in just a sec but a bit more background might be in order.....I'm not looking for the least costly option per se. I'm certainly not wealthy, I'm just looking for the best, balanced value....If the choice is to spend $500 five times or $2600 once, I'd rather spend it once, do it right and move on to the next step. I've tried doing things both ways and discovered that it's ultimately better to do it right the first time.....that's why I'm asking all of you....

Thanks for looking, I value any and all input. Questions will be answered as fully as possible so please ask!

Thanks.....Jeff

Welcome to CHR Jeff. I think your horsepower figure is going to be a bit high using mostly stock parts. Barry at Survival Motorsports is a very well respected FE builder and offers some reasonably priced, high quality FE parts...and yeah, a complete stroker kit for them too. IMO, anything beyond 400 horse is gonna be a bit much for the stock rods. Might want to wait to hear from FFR 428, he's around here often on some of his suggestions...but while you're looking, take a look at Barry's stuff!!!!!

This should be the web site--

http://www.survivalmotorsports.com/

Thanks for the warm welcome! I've previously been to Barry's site and he's definitely got the complete toybox!! Just wish I had enough cash laying around to hit "Order Now" about fifteen times....I figured the target would be a bit high with the stock heads and rods but I'd like to see how close I can get with the stock crank. I'll probably be bugging you guys for some time to come since I've got three of these blocks laying around and would like to build 'em all. Possibly build one with the stock iron to the safest level, sell it and move on to the next one? I only need the one FE for my personal ride...Actually "need" is a bit of a stretch since the car has a perfectly healthy 289 in it but....I've got a storage building that needs cleaning out and I just don't see any sense in letting this stuff go to waste. A couple of 351 Clevelands, some complete 302's and a 429 as well. I'm trying to switch from "acquisition" mode to "make it run-make it gone" mode.

Hey Jeff, welcome aboard and thanks for the obviously intelligent opening post.

I'm retired and enjoy putting together combinations on my playtoy, DynoSim version 4.20 software. I'm no different from most of the other motorheads on this forum, having wrenched on hot rods for 50 years, doing most everything from stock rebuilds to drag race motors, front end/rear end rebuilding to clip swaps, frame swaps and engine swaps (my favorite). Anyway, I'm 67 now and can't do many of the things (physically) that I used to be able to do, so I placate myself with this playtoy and passing on stuff from my noggin to others who can use it to their advantage. Many, many knowledgeable people have helped me in the past, so I feel a responsibility to help others with what I have learned. Now that you know who I am, let's tackle this FE.

I have built only a couple of these motor in the past, so I don't have all the detail knowledge that others on this board have, but in the end it's just another air pump and so will respond to the usual changes in my opinion.

There's a plethora of combos that will work for you, this is just one of them.

390 block bored +0.030".
390 crank
Rods: I'll leave this to others who have more knowledge of the FE
Pistons: Speed Pro L2291F30 forged.
http://store.summitracing.com/partde...0&autoview=sku
Heads: Edelbrock 60069, 170cc intake runners, 72cc chambers, 2.09" intake, 1.66" exhaust.
http://store.summitracing.com/partde...5&autoview=sku
Intake: Dual-plane, high-rise such as the Performer RPM or Weiand Stealth.
Carb: 850 CFM
Headers: large primaries, equal-length, long-tube. (real headers, not those cheezy shortie units).
Cam: CompCams 33-230-4 hydraulic flat tappet, installed 2 degrees retarded.
http://www.compcams.com/Cam_Specs/Ca...?csid=934&sb=0
Static compression ratio: 9.90:1
Dynamic compression ratio: 8.28:1
Volumetric efficiency: 102.8% @ 5000 rpm's.
BMEP pressure: 205.2 @ 5000 rpm's.
Juggle the block deck height and gasket thickness to achieve a squish of 0.035" to 0.045". With a tight squish and optimized ignition timing, this motor should easily run on pump gas with zero detonation.
RPM HP TQ
2000 160 419
2500 196 412
3000 248 434
3500 319 478
4000 388 509
4500 460 536
5000 512 538
5500 535 510
6000 550 481
6500 514 415
This cam clicks off like a switch at 6100. There's a dogleg in the torque curve at 2000-2500 that I don't much like, but I was able to minimize it by retarding the cam 2 degrees.

Now Jeff, there are many who poo-poo the results of these software dyno pulls and in some cases I have to agree with them that the numbers are optimistic. The beauty of the software is that you can COMPARE different parts and how they react with each other. It's not necessarily the definitive number, but the comparison that makes the software valuable. I tried 6 different cams, advancing and retarding them, 3 different intakes, 2 different pistons, 3 different carbs and 4 different static compression ratios to get the results shown here.

I have compared results from this software to hard-core dyno pulls and it seems to be within about 2% on the numbers.

I'll run some other combinations if I can find head flow numbers. If you come up with any, post them and I'll plug them in. By the way, here are the numbers on the Edelbrocks....
0.100 88 64
0.200 153 113
0.300 195 148
0.400 233 171
0.500 265 183
0.600 270 200

Originally Posted by Jeff Perkins

Thanks for the warm welcome! I've previously been to Barry's site and he's definitely got the complete toybox!! Just wish I had enough cash laying around to hit "Order Now" about fifteen times....I figured the target would be a bit high with the stock heads and rods but I'd like to see how close I can get with the stock crank. I'll probably be bugging you guys for some time to come since I've got three of these blocks laying around and would like to build 'em all. Possibly build one with the stock iron to the safest level, sell it and move on to the next one? I only need the one FE for my personal ride...Actually "need" is a bit of a stretch since the car has a perfectly healthy 289 in it but....I've got a storage building that needs cleaning out and I just don't see any sense in letting this stuff go to waste. A couple of 351 Clevelands, some complete 302's and a 429 as well. I'm trying to switch from "acquisition" mode to "make it run-make it gone" mode.

Hey Jeff, I'll probably never stop "acquiring" Ford pieces.... Matter of fact, I would be interested in knowing what Clevelan parts you may be willing to part with... On my "round-to-it" list is a couple of Torino's just begging for some high winding Cleveland horsepressure!!!!!

Tech's horsepower projections are IMO the most accurate I've seen on this site (and others for that matter).... It's definitely worth digging up all the numbers and data he needs for his software........ Hope you enjoy your time at CHR, there's a few of us Blue Oval guys here and we're always willing to give some advice and always ready to learn more about going fast with Blue Oval power!!!!!

Thanks for the quick, detailed responses gents, I really appreciate the insight! Hopefully someone else will have some information on rod choice. I'll be looking into the cam acquisition as well as the piston recommendation. I plan on getting this block to the machine shop within the next couple of weeks and I'll have to have the pistons handy for fitment to the new bores so thanks again for making up my mind on that. The best part? Summit is less than 15 miles from the house. Convenient to say the least.

Dave,
I've got two complete 2V Clevelands one of which is in my '71 Mach 1. I plan on building that one but the other one is certainly up for grabs. I don't have any detailed information on casting numbers or condition right now but wouldn't mind looking for you. I picked that one up at the same time as the Mach 1 and just stuck it in the building with the rest of the "I'll get to it later" pile. Let me know what you're looking for and I'll check to see if it matches your needs.

Again, thanks.

Jeff

Originally Posted by Jeff Perkins

Thanks for the quick, detailed responses gents, I really appreciate the insight! Hopefully someone else will have some information on rod choice. I'll be looking into the cam acquisition as well as the piston recommendation. I plan on getting this block to the machine shop within the next couple of weeks and I'll have to have the pistons handy for fitment to the new bores so thanks again for making up my mind on that. The best part? Summit is less than 15 miles from the house. Convenient to say the least.

Dave,
I've got two complete 2V Clevelands one of which is in my '71 Mach 1. I plan on building that one but the other one is certainly up for grabs. I don't have any detailed information on casting numbers or condition right now but wouldn't mind looking for you. I picked that one up at the same time as the Mach 1 and just stuck it in the building with the rest of the "I'll get to it later" pile. Let me know what you're looking for and I'll check to see if it matches your needs.

Again, thanks.

Jeff

No rush Jeff, just some casting numbers from the block and heads someday when you have time.... The 2V heads work good for a street Clevor engine......

Nobody has weighed in yet on the rods, so I did a little research. These look like good rods to begin with. I think I'd magnaflux 'em, have a set of ARP bolts installed, re-size the big end and call it good.
http://store.summitracing.com/partde...2&autoview=sku
Measure the diameter of the bolts in the rods now and then measure the diameter and length of the new ones before you lay out the cash for them. Better to find out now if they are the wrong diameter and length.

For 400-450 hp I wouldn't hesitate to do stock rods with ARP hardware. But honestly if your shooting for 500-550+ hp I'd look at the Scat H beams. After you rebuild the stock rods (ARP hardware, size and rebush) your close to the price of new Scats. Cheap insurance. Dave and Tech have covered things really well here. Just to add if you do look at the Edelbrock parts check with Keith Craft also. He can put together a nice combo package on pistons and rods too. I'm late for work but I'll check back later!!

Hmm, looks like I need to check with my machine shop for actual cost on the rod work to be done. He's very reasonable as well as being capable so the cost may not be exceptionally high. My concern is that with the power target I'm looking to hit, those rods will be at their limit and I don't relish the thought of a bottom end failure in the least.

Any thoughts on the HawksRacing H beam rods? They're available from The Mustang Depot for $350 a set, have ARP hardware, made of 4340, weigh 805g each and have stock journal sizes. They look pretty nice and the price is very attractive.

Regardless, I appreciate the input and Tech, you've been a great help so far!

It would be a shame to waste all the time and work cuz a rod let go and window'd the block!!! Never have ran a Hawk's rod, can't say that I've heard much good or bad about them....but then I'm one of them fools who spend the extra and go with Carillo's, Crower, or similar US made rod.... Lots of folks on here use the low buck imported rods with great results, I know Pat has used them in some big horse engines with no problems.

Jeff, you mentioned earlier that you had a 750 you wanted to use. I guess I missed that when I did the DynoSim. Go ahead and plan on using it, horsepower drops only 3 to 547 @6000 and torque drops 3 to 535 @5000, so no big deal and it will save several hundred in cash outlay.

I didn't go into detail on the block deck height/squish/piston deck height/gasket, but that's the critical area of the motor in my opinion. That's where you either have a motor or you don't in terms of preventing detonation on pump gas.

What you want to do is add up your "stack", the total of the crank radius, rod length and piston compression height and compare that figure to the block deck height. Of course you want to measure everything closely before final assembly, but you can get an idea of where you are before you ever buy parts. I believe the block deck height of a 390 is 10.170". That assumes that some knothead previous owner hasn't decked the block. The crank radius is 1.890", the rod is 6.490" and the L2291F piston has a compression height of 1.776". If you add up this "stack" parts, you get a stack height of 10.156". Deducting that from the block deck height of 10.170" reveals a piston deck height of 0.014" (piston in the hole 0.014" with the piston at TDC). Now, to get the squish, you add the thickness of the compressed head gasket to that. Most composition gaskets that are available are in the 0.040" thickness range, so using one of these will put the squish at 0.054", a little too generous in my opinion. FE gurus may have a different take on it. What I might be thinking is to take a light skim on the block decks (0.009") to just clean them up and set the piston deck height at 0.005". A 0.040" gasket such as the Ford M-6051-A427 added to the 0.005" piston deck height would produce a squish of 0.045". Or a 0.014" cut on the decks and putting the piston at zero deck with the 0.040" gasket would put the squish at 0.040".

I might be telling you stuff that you already know, but I'd rather repeat it than to have you make a mistake on figuring the squish for the motor. Of course you don't want to cut anything until you have done some careful measuring.

Now, for those of you who are just tuning in and haven't had experience with "squish", I'll expand on this for you. It is desireable to generate turbulence in the chamber just as the plug fires to prevent any "dead spaces" where the mixture wouldn't fire. This feature will serve to allow the motor to operate on a lesser quality of fuel or to allow it to operate on the available fuel at a higher static compresssion ratio, so long as the intake closing point on the intake lobe of the cam is matched to the static compression ratio to close the valve at just the right time to trap the mixture in the cylinder as the piston is ascending on the compression stroke. For a given static compression ratio, closing the intake valve too early can result in excessive cylinder pressure and the inability of the motor to run on pump gas without detonation. Closing the intake valve too late can allow too much of the fuel/air charge that has just been pushed into the cylinder by atmospheric pressure to be pushed back through the still-open intake valve as the piston ascends in the bore, pushing the mixture up the intake tract to disrupt the signal at the carburetor venturi. The venturi sees flow going both ways and doesn't know whether to sh** or go blind. This is what makes the rump-rump in an over-cammed motor at low rpm's. The carburetor venturi is incapable of metering fuel properly. If you get the chance to see a cammed-up motor run at night with the air cleaner off and a strong light shone on the top of the carb, you'll see the phenomenon of "stand-off". This is a ball of mixture that is being blown out the top of the carburetor by the piston coming up in the bore while the intake valve is still open. Once the motor gets "up on the cam", everything smooths out and you have a runner, but at low r's, you get the rump-rump.

Anyway, I'm getting off-subject. The point is to tighten up the squish so that the flat crown of the piston matches up with the flat underside of the cylinder head and results in the "jetting" of the mixture toward the spark plug, generating turbulence and optimizing the combination of parts. Here is a photo showing the underside of the Edelbrock head (photo showing the valves). On the right side of the photo, you can see that the head is flat at the area where the piston crown would mate with it. Think of it as dropping a book down on your desk and visualize the air that escapes as the book closes in on the desktop. That's what squish is. The other photo is of the piston. You can see that there is a nice flat area on the crown to mate up with the head at top dead center.
http://store.summitracing.com/largei...dl-60069_w.jpg
http://store.summitracing.com/largei...l2291f20_w.jpg

The dimension of 0.035" to 0.045" has been arrived at by professional engine builders who have experimented with this stuff and determined that this is the optimal dimension. Any wider and you have too much clearance for the mixture to be "jetted" across the chamber. Any closer and you run the risk of a piston/head collision. As the motor runs, things change. The crank flexes a little, the rods stretch a little, the piston heats up and gets a little taller and you end up with a very close clearance between the piston and head at operating temps and rpm's. David Vizard says he has run a small block Chevy at 0.026" with no collision, but that is not for the faint of heart to try.

Great stuff and no, I didn't know all of that. I will be putting that knowledge to good use though. Expect some updates and further questions as this build progresses.

As for rods, further investigation indicates that the cost difference between the Scat rods and the imports isn't as great as I'd initially thought so the better rods will go in.

Scat rods are on order and should be in soon.

Tech,
I just wanted to ensure that I'm on the same page here, the pistons that you mentioned are Speed-Pro's with a 4.070 bore (at least that's how I read it) and a .030 overbore was mentioned initially so wouldn't that require a 4.080 piston? If that's the case, I don't see that size readily available from Summit. I haven't had the machine shop check bore sizing yet but my initial measurements with the ol' Mitutoyo caliper shows that it might just be possible to get there from here. I've looked and a couple of companies make forged pistons in .030 over but the price is pretty steep. I really like the idea of forged pistons so I'd like to keep it that way....I realize that .010 isn't that great a change but I would value your thoughts on power production with that difference. Assuming I've got the math right anyway...

+0.030 is usually the first thing that pops out of my mind on these builds because a block will almost always clean up at 0.030", where it may or may not clean up at 0.020". I much prefer less cut on the cylinder walls, thinking that the walls should be left as thick as possible. In my opinion, the small amount of additional power gleaned from another 0.010" cut doesn't justify the thinner walls.