4-inch domed pistons

[Bob B.]

Hi all,

My '57 Lil Twister drag Corvette is in need of some high-compression pistons. I have a set of JE 156 4-inch pistons that came out of a 283 that had been, shall we say, bored a bit more than recommended. These are pic 151. I also have a 327 that has not been overbored at all that has the pistons as shown in pic 749.

Here are my questions:

• Would either of these be something that a '61-66 era drag Corvette would have used, or should I look for higher compression? If so, how much?
• If I can use either of these sets of pistons, should I use the stock 327 pistons or the overbored 283 pistons, seeing that both are 4-inch? I'm not sure which yields the higher compression.

Thanks,

Bob

[Joe L.]

Re: 4-inch domed pistons

Hi all,

My '57 Lil Twister drag Corvette is in need of some high-compression pistons. I have a set of JE 156 4-inch pistons that came out of a 283 that had been, shall we say, bored a bit more than recommended. These are pic 151. I also have a 327 that has not been overbored at all that has the pistons as shown in pic 749.

Here are my questions:

• Would either of these be something that a '61-66 era drag Corvette would have used, or should I look for higher compression? If so, how much?
• If I can use either of these sets of pistons, should I use the stock 327 pistons or the overbored 283 pistons, seeing that both are 4-inch? I'm not sure which yields the higher compression.

Thanks,

Bob

Bob------


You cannot interchange pistons between 283 and 327 cid engines. The stock rod length is the same but the compression heights are different.

The piston on the left appears similar to the 1962-65 SHP 327 piston. With 62-64 cc heads this piston produces a compression ratio of about 11:1.

[Bob J.]

Re: 4-inch domed pistons

Hi all,

My '57 Lil Twister drag Corvette is in need of some high-compression pistons. I have a set of JE 156 4-inch pistons that came out of a 283 that had been, shall we say, bored a bit more than recommended. These are pic 151. I also have a 327 that has not been overbored at all that has the pistons as shown in pic 749.

Here are my questions:

• Would either of these be something that a '61-66 era drag Corvette would have used, or should I look for higher compression? If so, how much?
• If I can use either of these sets of pistons, should I use the stock 327 pistons or the overbored 283 pistons, seeing that both are 4-inch? I'm not sure which yields the higher compression.

Thanks,

Bob

Piston pins are in different locations between 283 & 327 due to different crank stroke.

[Tom B.]

Re: 4-inch domed pistons

They both look to be similar to a factory fuelie piston which would be around 11:1 depending on head volume. 12.5 to 13:1 would be more in line with a '60s gasser motor.

The big question is what crank are you using?

The 283 pistons are for a 3" stroke and the 327 ones are for a 3 1/4" stroke. Put the 283 pistons in with a 327 crank and they will stick out the top of the bores 1/4". The 327 pistons on a 283 crank would be 1/4"+ down in the bore at tdc. Plus if you need a clean up bore you will need at least 4.030 pistons. I suggest some fresh 13 or 14:1 forgings in 4.030 to keep everything new and fresh.

Tom