Thread: help....thoughts? SBC 400

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Need some advice.....Im new to the SBC engine build scene. Ive got a SBC 400 bored 0.040. Planning on alluminum 64cc heads, 200cc runner, roller cam/lifters ect... trying to build somewhat of a "mildly hot" street motor with fairly aggressive (nice sounding) cam. Plan to not race it other than from street light to street light behind it will be a 700r4 for the occasional long weekend run
I think I may have went wrong on my piston choice...Ive got 15cc dished. Got the block back from being cleaned, new cam bearings, crank polished, freeze plugs, pistons put together ect. So I decided to see how far down in the hole the pistons set (goal of CR 10:1 - 10.5-1). Pistons are .040 down in the hole at least. Combine that with an 0.41 head gasket it takes the CR down to 9.6:1. Also just recently learned about "quench" which with the dished piston doesnt work out. What would be my best approach at this point.....New flat top pistons? Deck the block .040, but then that would change geometry by a fair amount? What I can figure is that standard deck would leave stock piston about 0.020 - .025 down in the hole and some aftermarket pistons add to that by .020 sometimes, giving me my .040? Or am i thinking about this too much and I just need to run with it at 9.6:1 and .081 piston head clearance, will I be able to produce 400HP with at least 400 torque??? Looking for advice, or if im being an idiot would appreciate knowing that too! Will much appreciate any recommendations you guys may have!!

What is the piston part number?
What is the block deck height?
Are you stuck on 64cc heads? Profiler makes an excellent and affordable set of 70cc or 72cc heads that will support 500 hp in your 408.
http://www.profilerperformance.com/r.../sbc-23-degree

Keith Black makes a nice hypereutectic piston that would produce about 10.5:1 SCR with a 72cc head. Most builders will agree that 10.5 is the limit with today's pump gas.
https://www.uempistons.com/index.php...roducts_id=594

I would cut the block deck height to 9.008" (zero deck with the KB pistons shown above, when used with 5.7" rods. Scat 25700P will clear the cam lobes.), then use a Fel-Pro 1014 gasket (0.039" thickness) to set the squish at 0.039". Any aluminum head manufacturer will specify a composition gasket to be used with their heads. The 1014 has pre-flattened fire rings to help prevent brinelling of the heads, as well as having steam holes.

If you are open to this suggestion, I will explain the details of this build for you, along with the proper cam, intake, carb, headers, etc. Are you open to laying out 600 bucks for a retro roller hydraulic cam and roller lifters? Howards makes an excellent product for the price.

If we never hear from you again, you should know that the heads will have to be drilled for steam holes. The manufacturer will drill them for you or you can do it yourself.....
Technical Articles at Greg's Engine & Machine

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Piston part is 400AB (i think, at work right now cant remember exactly) sealed power pistons. Havent actually measured deck height other than how far down the pistons sat. How do I measure the deck height? SBC stock is 9.025 correct?
Yeah on the 64cc heads, good price, probably not the best available by any means but the price is right $700 comeplete for the set with 2.02/1.6 valves and springs set for .60 lift. They will be drilled with steam holes already. Yes on roller set up, have been looking at howards actually. I just dont know how to correlate the numbers to how it will sound. I want the perverbial "best of both worlds" a nice lope with usable power band. carb i was thinking along the 750cfm route, intake: edelbrock performer, long tube headers. Looking to build a street engine that will fry the tires when the time is right, and sounds "healthy"........ based on cam then i would choose the correct torque converter for the 700r4.

I'll offer three comments and then back away and let Tech run 1) Set your engine up for power and efficiency and the sound will take care of itself. 2) Biasing your decision on any part to achieve sound at idle is one of the biggest mistakes you can make. 3) Open your mind and listen carefully to Tech. He knows of what he speaks, and if you follow his advice you're gonna have a perma-grin that won't fade for a long, long time.

rspears - your absolutley right, thats what I needed, im getting lost in all the stuff that I think i might know or am just learning vs. what I actually do know, which isnt much!!........it takes a reminder like that to realize that there are others out there that have been there and done that. If I set up the motor up to make decent power then by default it will sound appropriate. I do have an open mind and yes will take Tech's advice, the only thing Ive got to keep in mind is how deep my pockets are

Tech - The only thing I know right now is that I need to stick with the 64cc alluminum heads 2.02/1.6, 0.60 spring, steam holes drilled (already purchased), my rods are stock (would prefer to save the money and stay with those?)beyond that I am very open to advice. I take it I need to measure my deck to know exactly where Im at. Then what would your recommendation be?

Sealed Power 400AP pistons would not be my choice. They are what is known as a "rebuilder" piston, because the compression height is 0.020" shorter than the blueprint compression height for stock pistons. Another reason is that they are designed for use with the short 400 rod (5.565" center to center) that I wouldn't use. The side thrust was manageable when the 400's were new and being fitted to station wagons and suburbans and such, because the driver's of those vehicles were not interested in swingin' the crank to 6000 rpm's. But higher revs used in the hot rod fraternity will need a longer rod, 5.7" or 6" to help minimize piston side-loading and scuff. I don't like having to use a spacer rail to prevent snagging the oil ring in the wrist pin bore, so I shy away from using 6" rods, preferring 5.7" rods where the oil ring does not intersect the wrist pin bore.

The 24cc dish on the 400AP piston leaves a lot to be desired also. It leaves little or no flat plateau on the piston crown to mate up with the underside of the cylinder head to facilitate squish. I also don't see myself using a cast piston at 6000 rpm's. Hypereutectics are also cast, but have an overage of silicon in the mix that makes them superior to standard cast pistons in my opinion.

You can measure the block deck height yourself if you own a 12" caliper, either a dial type or an electronic type. Even a simple vernier caliper will work if you know how to read it. Here's one on Buy It Now for 33 bucks.
12" 300mm Precision Vernier inch Metric 4 Way Caliper | eBay
Here's one with a case for 29 bucks....
Inside Outside Vernier Caliper w Case 12" | eBay
Here's a cheezy offshore dial caliper for 49 bucks.....
12" Precision Stainless Steel Black Face Dial Caliper New | eBay
My best advice is to sidetrack the electronic units. My experience is that every time I reached for my digital, the batteries were dead.

Hook one jaw onto the machined surface of the main bearing bore like shown and hook the other jaw of the caliper over the block deck where the heads bolt on. Add 1.420" to the measurement you get from the calipers. 1.420" is roughly the radius of the main bearing bore on a 400 block. So, for instance, if you read 7.605" on your calipers and add 1.420" to that, you find 9.025", the blueprint dimension for block deck height for all Gen I small block Chevies. Do this measuring on all four corners of the block to find if the block was milled catty-wampus at the factory. It's not at all unusual to find the decks machined uphill or downhill from one end to the other. Simply visualize a chip that lodges itself in the register when a new block is being loaded into the mill at the factory and you can see how easy it would be to mis-machine the block by ten to fifteen thousandths or more. (0.010" to 0.015")
http://www.jamisonequipment.com/picPage/BHM-24-1.gif

Note of caution: Look at the jaws of a caliper. The last 1/4" or so is sharpened like a knife edge. This is to allow the machinist to read the diameter of a circle or other curved part. If the jaws were thick all the way to the end of the jaw, you would get an erroneous reading because of the gap between the part being measured and the jaw of the caliper. What I'm getting at is, use only the very tips of the jaws of the caliper to measure the block deck height. Eyeball carefully to see that you have the same amount of jaw on the parts on both jaws of the caliper.

For the rest of you fellows out there who are interested in measuring the block deck height of your SBC, see page two here, where it says "Main Journals". This is the measurement less bearings, just the raw bore.....
http://www.theengineshop.com/product...f_file-124.pdf

I was busy typing and did not see your posts 5 or 6 until after I posted this.

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It looks to me like you're trying to poor-boy this build and make a silk purse from a sow's ear. I don't think I need to be involved any longer because I feel that all I'll encounter is resistance when I suggest doing it properly. Some of the other fellows will wade in with info for you. Good luck.

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Thank for the how-to on measureing deck height. Didn't mean to burn any bridges here, didn't exactly say no to any of your suggestions either, but i would imagine being on a forum you have run across more than your fair share of folks that argued with you regarding your suggestions. Not exactly trying to "poor boy" the build, but I do have a sense of reality, and financial stewardship isn't what i would call a bad thing for myself, a few things that most people in this world seem to not have a grasp of or not understand these days.

Thanks for your input thus far and thanks for bowing out graciously.

When I decide exactly what direction I'm gonna go…..and get it all done, ill let you know how it turned out.

Sounds to me like if you were open to new pistons and rods to go with them then Tech might wade in again? Not sure that's all it would take, but.....