[78 chevy truck]

k i just put my old pistons back in th eblock to see if they deck the block from the last rebuild and i think they did. the pistons that were in there were the cheap sucker pistons with 20 off the top and the come even with the deck.so is this good or bad for my comp?

[78 chevy truck]

any one

[crazy larry]

compression will be increased, you'll need to measure several things in order to properly determine your comp. ratio.
but if it was just a regular everyday motor, not hi-po, you ought to be allright. but measure everything to make sure.
i hate building grenades.

if your pistons deck out flush, you'll need to check valve clearance....

[78 chevy truck]

my heads are 72 cc heads and the vavels and in the head a bit

[Thom Laybourne]

I would be careful with piston tops being that close to the top. Warm that engine up and run 5k on the tack. Your rods should stretch about .005-.010 This could cause the piston to hit lip of head. GRENADE You can put a piece of clay on piston and bolt the head down. Then remove head and check the clay for clearance. I do that a lot with dome pistons to check valve clearance.

hr41pearl

[78 chevy truck]

what if i use a thick head gasget

i am going to be useing the summit rebuild kit

befor i tore down my engine it ran fine with thos heads. can i still run a pretty big cam then? i need to make this engine work

[Thom Laybourne]

Question. Why are you decking the block? Heads are decked because they can warp. Blocks very rarely are decked. Even with the gasket I would check with clay. Piston comes up / hits gasket / where does gasket go? Felpro is my choice and I would check even with them. Most gaskets will not crush out to the cylinder, but why take the chance.

hr41pearl

[johnsongrass1]

You need to just clay the clearances and limit the cam to a total duration of 290 or so. IF the deck were cut than the stamping numbers would be missing as well. It's unlikely the machine shop would worry about re-stamping the numbers. Did you check the deck with a dial indicator and bridge or are you eye balling it?

[78 chevy truck]

the numbers are off the block deck. it was done before i bought the truck. what should i do. the pistons i have are the sucker pistons. are summits like that. i dont have money to get a new block i need help.

[Thom Laybourne]

Sorry, I have never heard of a sucker piston. Can you describe it? Before you go much further, I would still use the clay and find out what you are dealing with. The horrible thing in life is our imagination. Reality is no comparison. This also must have started life as a different thread. What is the block size? A little history will work wonders here. Junk yards are YOUR friend. All does not have to be NEW.

hr41pearl

[78 chevy truck]

a piston the has 20 thouthanys off the top of it. i just put one one my heads back on and turned the crank and piston to see if it hits the head and it does not. that is with no gasket. this is a 350 small block

[Thom Laybourne]

OK. Sounds good. Could you mic the clay or was it obvious that it had clearance? Sounds like the stock Felpro should work just fine. Compression should be about the same since you decked the block and the pistons. Now what do you want to do? Stock bore with a good hone? New proseal rings? Bearings? Good investment and low cost is balance the system. Little money - roller rockers. Good torque return. When you are back and running and think you are good - try a dyno shop tune. Money yes, but I have never had anyone tell me that it was a waste. Most people don't know until they have tried it. Dynoed my wife's 97 Honda. It is a V6 and boy was she surprised.

hr41pearl

[78 chevy truck]

bored 60 over newer heads 882 750 holly need help picking a cam want to make around 400 hp.

????????

[78 chevy truck]

ok were there is the pad on the back of the deck were there are some numberes i only have a c bye its self. could they have just claned up the the deck a bit

[Thom Laybourne]

Sounds like you will be OK. Your compression will not be over 10.0 by the sounds of it. Today they talk about horse power at the rear wheels, so I don't think I can help you there. Trannys / rear gears / tires all factor in to the HP formula. Since you are not running a high compression engine and are running a larger carb, I would look at ISKY.com They have two up there that will give you the 400HP at the fly wheel. Maybe look for killerformula here and ask him for a recommendation. He seems to have a better handle on tight specs. But if you can afford it, look at rollers. Torque is a much underrated thing. The torque you save with rollers is DIRECTLY transferred to the rear wheels. NO LOSS.

hr41pearl