I'am putting together a 496 stoker motor and need some help on what pistons I should run. I have Edelbrock RPM heads , semi open 110 cc. , and Edelbrock cam, int-.560 exh-.573 duration; int- 240 ext.-246. I have the chance to buy a rotating assemble kit that has speed pro .280 domed pistons. What would be the compression ratio of this combo and would this work on pump gas? Thanks alot for any help anyone can give me.

Originally posted by p/lineman:
I'am putting together a 496 stoker motor and need some help on what pistons I should run. I have Edelbrock RPM heads , semi open 110 cc. , and Edelbrock cam, int-.560 exh-.573 duration; int- 240 ext.-246. I have the chance to buy a rotating assemble kit that has speed pro .280 domed pistons. What would be the compression ratio of this combo and would this work on pump gas? Thanks alot for any help anyone can give me. What's the piston dome volume or part number?
A 280 dome doesn't mean much you need to know the volume in cc's.

I believe they are SRP # 4032, don't know the volume. The kit is the stroke kit from Stroker Motors # EB 4962, off web site. thanks

PS. know anything about stroker motor? The kit from a guy I know who bought it new about a year ago and never used it. I'am hoping it will work with the rest of my parts I already have. thanks again!

The 4032 is the material the piston is made out of.
A 280 dome sounds like the 30cc "10.25" compression piston but this is with 118cc heads.
You are gonna have about 12.0, with your heads assuming they clear the dome.

And yes, I have built a "few" stroker engines :D

.Hey Mike, I mean't the Stroker Motor company that is selling kits on the web. That is were the EB 4962 # comes from. I've been on your web site and talked to you before (you know stroker motors!) Sounds like the compression ratio is going to be too high for me. They don't much info one the site. Looks like they have on thats 9:1 @ 118cc and another thats 10.2 : @ 118cc I'll have to try to find out from the guy who hsas the parts which one it is. Would the 9:1 @ 118cc. work? thanks again for the info, as you can tell I don't know much about this.

Found the out the number on the pistons, it's H603CP .60 059-02-03-A. Hope that helps to figure this out. thanks alot, Jim.

Mine has Merlin 118/119 cc ovals on it and and .025" down in the hole ROSS about .150" or 3/16" tall domed pistons.. Sorry, I forget??

Anyway, I figure that with standard .022" steel shims I'm very close to or right at 9.8 to 1 CR. if this is any help to you.

You might check your pistons over to see if they are solid domes b/c if they are, you can machine them down to whatever CR. you want to match your motor's other spec's!! (Headgasket thickness -shim vs composite, down in the hole, chamber cc, etc...)...

Just an idea..

pdq67

Thanks for the info, I have the number off the piston and think they are SRP but can't find that part # anywhere. Maybe the number on the piston and the part number are not the same?

It's a Fed Mog Hyper coated piston, don't have the numbers in front of me but I believe it is a lot less dome than .280. ;)
Man,, are you confusing me,, Speed Pro to SRP to Hypers in three posts :D

Sooooooooooooooooo........ anybody know what this part # (H603CP)is and what comp. ratio would be with 110 cc. heads?????

Mike , told you I did'nt know what the heck I was doing!! thanks for your patience. I got a post ahead of you. Tried to find that number on SRP sites and could'nt find nothing that looked close. I don't want to buy them if they won't work but don't want to miss and go deal either.thanks again

Jim, It is a .280 dome but only 23cc.s.
That's why you can't just go by dome height.
It should be about 10.3 with your heads ;)

Mike, I found a # H693cp coated skirt piston on TRW site. This assemble has been sitting on the shelf for about a year and maybe they changed numbers from H603CP to H693cp. The H693cp is .230 dome and 9.97:1 with 109.4cc. I think this is what they are, thanks very much for your help! Jim

Jim,
I forgot you are a 496 & used 454 to calculate compression so if it is the 603 the compression will be 11.3 not 10.3
And the HP603CP is a good number & is for the 4.250 stroke so you need to know for sure what piston you have.

Mike, with the cam I have will I be able to run pump gas at that ratio?

Originally posted by p/lineman:
Mike, with the cam I have will I be able to run pump gas at that ratio? =
What kind of "pump gas" are we talking about??
At 11.0 I think you would be pushin it. ;)
If I were doin the engine I would advise against it.
What are the intake seat timing numbers on your cam?
Plug the numbers into Pat's calculator & see what you come up with.
Also, I ran the compression with a stock deck block which assumes the pistons are down about .020 so the compresson is kinda an uneducated guess :D
It may be up or down a little.

Pump gas would be 91 octane. I'am starting to think this package may not be right for me.Hate to put it all together and have problems. I don't know any of that cam info, hell I already told you MORE that what I know and a bunch of things I did'nt!! It's one of thoses things thats a deal and you hope it would work. thanks