Ok Guys,
Need Some Help....whats The Difference Between The "088" And "934" 502 Heads And Which Is Better?
Also, Which Is The Best 502 Block To Use? I Have A Gen6 502 With The Casting# Ending In 300 And A Set Of "934" Heads.
This Is What Im Building.....516 Ci, 9.3-9.5 Compression, Hyd. Roller Cam (havn't Decided On The Specs Yet But Know Lift Will Be Between .550-.600(split), Duration Will Be In The 230's-240's(split) With A 112 Lobe Seperation ), Roller Rockers, Srp Pistons(.60 Over), Scat Rods, Factory Crank, "934" Heads(stock But Freshened Up), Performer Rpm Air Gap, Holley 950hp, Msd Ignition, Milodon Oil Pan, Lightning Headers.
Looking For 525-550 Hp. What Do You Think Guys....is It Achievable???????

12562934...00-up...rect...OPEN...Gen.VI 502 Marine
14097088...91-up...rect...OPEN...Gen.V 454/502 HO, 118cc chamber

I believe the heads are the same as far as performance goes. YOu should have some minor port work done to them. The HP you are trying to get can be made by accident on a 502. If you don't have to bore it .060, don't do it. Just go .030 over. Also, the carb you listed is too big. An 830-850 is plenty.

As Griff said
I had a 509 9.5/1, crane 741 cam w/ Lightning headers with 850 and it was running a little rich.
Don't take your block to .060 over if you don't have to. This way if you blow it up/score a cylinder you will not have to sleeve a cylinder, you can just bore it out

thanks for the reply.....
i wasn't sure about the carb. i have been also kicking around the idea of using a 830 (just not sure how well the annular boosters will work). the motor isn't going to turn over 5,500 rpm. good info on the heads. i have seen a lot of 088 heads for sale compared to what i have and didn't know if it was because the "088" heads are just a better head. i hear you guys on not boring it to 60 unless i have to but unfortunately i cant get the cylinder that's scored to clean up at 30 over. believe me, i wish i could.
Griff, what did you mean "The HP you are trying to get can be made by accident on a 502." and what porting would you recommend?
thanks again guys, mark

At .60 0ver on a stock 502 you are at 4.53, a 502 block will easily go to 4.56, so he has a bore left in it still.

hey tx911,
those srp pistons arrived yesterday. they look great. im very happy with them! please send me a shipping quote to my email address for the other item we talked about on the phone and i'll send you the money. thanks mark. it's nice to deal with an honest person!

4.56 and above should really be sonic checked to be sure the block is thick enough.
http://www.offshoreonly.com/forums/g...-hp-500-a.html