Thread: Build help for small journal 327

Tweet

So I want to build a small journal 327, its got stock steel crank, stock rods with flat tops. Not sure on the pistons in it, they have a big gap just under the oil ring about the size of the oil ring. So the skirt is not attached to the ring section of the piston except on each side by the rod pin bushing. If it does not need boring will these piston work ok and whats the max Compression I could get with these flat tops with small cc heads (?). Or should I bore it and put new pistons to get to a higher compression ratio. Would like to get 400 nto 450 HP out of it but want to be sure its going to hold up to that. Anybody have any recipes for building this motor?

Pistons? Cam? solid or hyd? Heads? Rods????????????????????????????

It seems like every couple of weeks this question comes up.
First let me say that your expectations of 400 to 450 hp out of a 327 are not practical, not naturally aspirated anyway. Making power is a function of moving air through the motor, the more air you move, the more power you make. The smaller the motor is, the higher you have to rev it to move the air through it. For instance, a 350 bored and stroked to 383 will move 665 cfm at 6,000 rpm's at 100% efficiency. To move the same amount of air through a 327, you'd have to rev it to just over 7,000 rpm's. Now, here's the kicker. In order to make power up to 7,000, you'll need more cam and more compression ratio than you would with the 383 and once you start that, you're moving away from a street motor and into the realm of a race motor. You see, any cam you install in the motor will have an operating range of about 3,500 rpm's. In other words, it will make power from 1,000 to 4,500 rpm's or 1,500 to 5,000 or 2,000 to 5,500 or 2,500 to 6,000 or 3,000 to 6,500 or 3,500 to 7,000 or 4,000 to 7,500, etc., etc. So you see, in order to make power to 7,000 or 7,500 like you'll need to do with a 327, you'll have to give up power in the lower rpm ranges where you need it to be a street motor. Now, if you are only going to race the car, then o.k., no problem. If you will drive it on the street, then you will need steep rear gears and a 5 or 6 speed trans or if running an auto, you'll need a very loose converter and that sometimes is a pain in the ass because the converter won't lock up and will build tremendous heat when driving around town, etc., etc.

I'll let you digest what I've said here and get back to me with any questions you may have before I continue. Yeah, I have a whole lot more to say depending on what you come up with.

I will only drive the car once and a while, maybe 1,000 miles a year. Not worried about being a street motor, I usually stay on the local roads at 50 to 60 MPH. So I was thinking 11:1 or as high as I could go with ported big valve heads and a decent solid cam. Going with a T400 trans with I don't know maybe 2000 stall???(or I have some powerglides i could use) and 4:11 gears. I am curious on the heads I see 195 cc runners up to 215 or so, is that the amount of porting in the runner? how big of a head can be run on this set up? I was comparing my expectations to the stock 327 that made 365 HP or whatever the HP was on that motor, or was that motor already pushed to the limit? Seems I could built it a little better than that one and at least get to 400HP?

How much money do you have to spend? Are aluminum heads in your budget? Is a supercharger or turbo in your budget? Forged pistons? Good rods?

The 365 was a max effort from the 327 and was an 11:1 motor with a very long cam.

Don't need the thing running for about a year or so, i'll be rebuilding my shop and other projects along the way, not looking at a budget i was going to spread it out over some time get the block work done now and maybe next month buy some rods, maybe two months after that buy a cam setup few months after that buy an intake and carb and so on and so on. Money was one concern on heads I see them fro 1,000 up 1,800, i know I at least need some for $1,000 and would not mind spending an extra 800 if it would help. Heads and trans build would be my last two things to buy before completing it. Still need a little work done to the car before putting the motor in it (68 camaro). I actually have a source to get some turbos but am not impressed with my buddies luck with his twin turbo350 as far as maintanence goes. He had his first set and damaged one of the impellers, he said I could have the other single or both and rebuild the second one but I think I better keep it to non forced induction.

Originally Posted by chevydrivin

So I want to build a small journal 327, its got stock steel crank, stock rods with flat tops. Not sure on the pistons in it, they have a big gap just under the oil ring about the size of the oil ring. So the skirt is not attached to the ring section of the piston except on each side by the rod pin bushing. If it does not need boring will these piston work ok and whats the max Compression I could get with these flat tops with small cc heads (?). Or should I bore it and put new pistons to get to a higher compression ratio. Would like to get 400 nto 450 HP out of it but want to be sure its going to hold up to that. Anybody have any recipes for building this motor?

Pistons? Cam? solid or hyd? Heads? Rods????????????????????????????

If you have not started on the project yet I would consider building a 383 instead.
First it will make more torque so you don't need a steep gear or a really loose stall.
You could build a mild 383 with flat top pistons, good heads and a cam not much larger than a rv cam say 230 at .050 and make 400 hp on pump gas.

Thats what everybody says.... Build a 383 build a 383. I can't see building a 383 when I already have a good 327 block with a good steel crank. Besides that won't the 327 turn a higher RPM than the 383? Just my thoughts, I would rather have a 400 hp 327 rather than a 400 hp 383. Anybody can get 400 hp out of a 383 like you said its easy, flat tops rv cam................
I do appreciate all the info but I am pretty much set on building the 327 rather than anything else, just wanted some input on if it will hold up to what I am wanting to do with it.
Fact is I want a loose stall and a steep gear.

Yep you probably will get 400 HP out of a 327. But at what rpm ? Higher up the rev range. So to put it roughly, you will make 400 with a 327 but you will use more fuel than a 383. Why ? because just by the size of the 383 stroke 3.75 " they produce their power by torque, down in the low revs. But still a high reving 327 sounds great. It's all up to your personal choice. I am building two radically different motors one is a 383 the other is a 302, both chevys, both share the 4.00 " bore. The 383 is to have fun with, the 302 is a resto and I happen to like high rpm shift changes and the car it is in only goes out on a fine weekend when finished.

PS why not a 350 ? Build them all the time for people, good motor, great motor, but I like experimenting with something else

"I think I better keep it to non forced induction."

O.K., then it's going to have to be some good heads, 11.0:1 minimum c.r. and a long non-hydraulic cam. You'll have to run a tight squish to facilitate pump gas.

My recipe for such a beast might go something like this.....

Magnaflux and bore the block 0.030" to 4.030", cut for zero deck
Magnaflux crank, grind to next undersize if non-concentric, micro-polish
Eagle rods, I-beam, bushed for full float (H-beam preferred, but expensive)
SRP forged pistons, pop-up, part #147752, 11.4:1 c.r. with 68 cc heads
7 qt. oil pan, high volume pump, windage tray, crank scraper
Air Flow Research 195 heads, 68 cc combustion chambers, chambers altered by AFR to accept SRP piston pop-ups.
Edelbrock Performer RPM Air Gap intake. There are those who would argue that a Torker II would be a better choice and they may be right. The increased volume that each cylinder would see would help to cushion out the reversion that you will experience with a cam of this size. A Victor Jr. would be too large for this motor in my opinion.
Holley 0-4779 750 cfm carb.
Fel-Pro 1003 head gaskets, 0.040" squish with zero deck
Fel-Pro 1205 intake gaskets
Fel-Pro 1404 exhaust gaskets
Isky Z35 solid lifter flat tappet cam, duration 288 @ advertised, 254 @ 0.050" tappet lift, 0.525" valve lift, ground on 108 degree lobe centers. Will rev to 7,500 with Isky engineered kit (highly recommended).
Roller rockers
1 3/4" equal length headers into 3" collector, reduced to 2 1/2" pipes to the back. Mufflers of your choice.
Cold outside air to carb. DO NOT UNDER ANY CIRCUMSTANCES ALLOW THIS MOTOR TO BREATHE UNDERHOOD AIR.
HEI distributor recurved by Performance Distributors, Memphis Tennessee. 12 degrees initial, 24 degrees mechanical advance.
T5 5-spd rebuilt by G-Force for 600 ft.lbs. torque, 4.10 to 4.88 rear gears
Pedal to the metal and side-step the clutch, shift at 7,200

Are ya grinnin' yet?

Installation instructions for AFR heads....
http://www.airflowresearch.com/sbc_install.php

Exactly the kind of info I am looking for. So the 195 heads are big enough? Are the other ported heads to big? And you think the small journal block will handle it all?

AFR 195 heads will support 500 horsepower in a 383 @ 5,500 rpm's. (610 cfm @ 100 % efficiency). A 327 turning 6,440 rpm's passes 610 cfm @ 100 % efficiency. Is there any reason not to think the 327 would make the same power?

You do raise a good point about the block. I forgot about the main caps. It seems like I've read that they're good to about 400 horsepower or maybe a little better, so a change to Milodon 4-bolt caps in the three center positions would be real good insurance.

Hey, who knows, I might be full of hooey. Some of you other guys should jump in here and play the devil's advocate for me.....

Originally Posted by DennyW

In 1965 they had a 327 with 365 HP, unless it was fuel injected, then it had 375 HP.

The 375hp/327 was first introduced in '64 in Vettes with FI. The cam was the Duntov 30/30 and Isky came out with a comparable grind. I still have an Isky 30/30 and it will make power to 6000 plus. I've wound it a little tighter than that ,but it's hell on valve springs.
Summit carries the Isky version part # ISK-200030.

And balance everything to within a knats wing on weight!!! Little inch motors will make power but you have to zing them. A quality balance job is critical to longevity on them.... As NTF said, engines are a bit tough on valve springs when they run high (6500 and up) RPM, so plan on some extra maintenance keeping an eye on valve spring tension. Solid lifters seem to cause higher wear rates on the springs then hydraulic cams, roller cams with the radical ramps slam the valves even harder so the valve springs tend to lose tension and or break more frequently. Valve clearance is critical for perfomance and longevity also, follow the cam makers recomendation and check them frequently.... Oh yeah, run a rev limiter for insurance on missed shifts....

how 'bout ceramic coated pistons and heads, and put it on the juice?
( nitrous )

I like TechInspector's build recommendations. Pay close attention to the fact that he recommends a manual transmission. That 327 is going to build high rpm torque and hp at the expense of bottom end grunt. You would be very unhappy with an automatic tranny behind this combination. There will not be enough bottom end torque to launch it properly, even with a high stall converter.