[Stans Customs]

I'm really trying to determine the "compression ratio " and/or the piston type (flat tops or dished ??)a sbc 400 cid engine (#3951511) with 76cc heads (#'s 3998997) has. I believe this is a 1972 4 bolt main engine....would like to know if the front pad nos. can tell me what compression it is and verify that it is a 4 bolt main.

The numbers on the deck pad in front of the right head are..

12S216538 TO217CKP

Can anyone help me with this information..I can't pull the heads unless I buy the engine first.

Thanks .. Stan

[HOGDADDY]

Originally Posted by Stans Customs

I'm really trying to determine the "compression ratio " and/or the piston type (flat tops or dished ??)a sbc 400 cid engine (#3951511) with 76cc heads (#'s 3998997) has. I believe this is a 1972 4 bolt main engine....would like to know if the front pad nos. can tell me what compression it is and verify that it is a 4 bolt main.

The numbers on the deck pad in front of the right head are..

12S216538 TO217CKP

Can anyone help me with this information..I can't pull the heads unless I buy the engine first.

Thanks .. Stan

all 400's came with dished pistons and if it has 3 freeze plugs per side it is 4-bolt main however there are many that feel the 2-bolt is better block but if the block is not cracked I would use it. BTW THE NUMBER CKP must be wrong I dont see this code.

[Stans Customs]

Curious to know why some think that the 2 bolt block would be better? Also ...The pad stamping is very clear and the motor is sitting on a pallet so its easy to clean and look at. I'm absolutely positive the CKP is correct...

Have you any idea what the compression ratio is with dished pistons?

Thanks for the reply...Stan

[MI2600]

As far as I know, the 400s came with dished cast pistons and ran 8.5:1 compression with the 76cc heads.

[Stans Customs]

Thats about what I imagined...just don't know why I thought that. Been a long time since I messed with one of those engines...I was hoping that it was a little more and had flattops.

Thanks again ...Stan

[47 Coupe]

In my book the code CKP shows either a
1972 400 two barrel 170 Hp RPO LF-6
or
1980 267 2 barrel 120 Hp RPO L-39

Gary

[GoneNova/406]

all 511 blocks are 4 bolt and the 509 is 2 bolt.i have both of these blocks and the 509 is both 12 lbs. lighter and smoother or cleaned up sight wise.the webs between the mains are heavier duty and most racers seek these blocks out and turn them into 4 bolt blocks.any good 400 block 2 or 4 bolt will work well for most anything you want to do on the street within reason.400-500 h.p. should be no problem.take the short rods out if at all possible and replace them with 5.7 350 rods or longer if you can because the short rods load the side walls with to much press. and cause's them to wear elongated grooves in the piston track on the side walls.the longer rods will also give ou a broader torque curve.the dished pistons shouldn't be a problem depending on what you want to do with the motor.there are many ways to make power and or h.p..if you only want the motor to work for you the pistons won't be a problem.you can get good hypereutectic pistons for about $170.00 at racers outlet on ebay.the 997 heads are good and you can make them 2.02/1.60 very easy and cheaply if you can take them apart and put them back together yourself and again check racers outlet for the valves cheaply.none of the 400's ever got any good c.r.'s since cheavy used them to do work,but thats easily changed.oh the CKP code is in my book a pass. car,170 h.p.,1972 with th-350 or 400.probably a station wagon.

[Stans Customs]

Thanks Gone Nova...

Next question since you have a handle on this...

I have a 1980 Silverado SWB I put a destroked 400 years ago. Its is a 400 block with a 350 crank..(spacer main bearings).

The number on that block is 330817..... What about that block. Two bolt I believe.

I'm doing some engine shuffling. I can buy the running junk yard engine for $300 with a turbo 400 trans. It was in a 71 Chevy 3/4 ton pickup. Runs good but one of the heads has had the sparkplug hole drilled way out and a weird one installed..

I'm thinking about building a fresh engine for the old '80 Silverado and putting the destroked engine in a Kayot deckboat I bought with a freeze damaged 350. The destroked motor was a race engine and has a little too much piston to cylinder wall clearance for a daily driver (uses a bit of oil). Never fouls plugs or anything...plus I thought a stock 400 would be better for the pickup.

....and the destroked engine is internally balanced and would bolt right up to the heavy boat flywheel and hub....whereas I would would have to figure how to balance that stuff for the stock 400.

Then somewhere down the road I would really get serious about a good rebuild on the stock 400...while my old truck is still mobile till then.