502 crate

[cyclone]

love my 502. you might try and find a used set of the gm performance parts aluminum heads that come on the zz502. they work really well too.

[victorfb]

mike.. i love your 502 aswell... that thing ran awsome. i never got to get too much info on what you got into it, though i do remember you saying your cam is pretty big. probably a little too much for me and what i want to do with the boat. i know it is not just the motor though. your set up works very well. i may be looking for a differant hull as i am leary about putting the 502 in the tahiti. even if i get half the HP from my 502 than what yours has i dont know that the tahiti will hold up. my building partner has a 78 rogers bonneville he bought new and has maybe 40 hours on it total. ive been trying to get him to part with it but he keeps giving me the runnaround. it would allmost be a shame to swap motors on that thing too though since its all original. 405HP 454. he even has pics of it as it was being built at rogers. took a few every time he stopped by to check on the progress. now thats cool to have. anyhow. as for the ZZ 502 heads you mentioned, that would be nice to find, but i have a feeling i will be running the edelbrocks. still havnt got in touch with my buddy that has the hook up. (wife had cancer but operated on 2 weeks ago and seems to be doing great). so i didnt want to push the issue. what chamber size did you use? the oval ports have 110 cc and would bring me to about 9.5 to 1 i think, but the rectangular heads have 118 cc chambers. keeps me at about 8.8 comp. as i remember figuring. its a tough call.

[Dennis Moore]

The heads used on the 502/502 are the same as the Edelbrock heads (Edelbrock makes them for GM with the GM logo). The camshaft is what makes that engine run, it is good for a marine engine and is a fairly mild grind.
Sincerely
Dennis Moore

[victorfb]

thanks dennis. i did know that edelbrock made the heads for GM but not sure which ones they used. oval or rect. and i dont think the 502/502 heads are the marine version. but what do i know, i just swing a hammer.
the cam from a 502/502 would most likely satisfy me as im not looking to be the fastest, just want some good HP and a long lasting motor.
hey mike (cyclone) what did you do with your stock cam? wanna sell it?

[HOSS]

Deffinately change the cam and oil pan. Other than that jam. Pistons and rings? No. Bearings? No. Heads? No. I like the Victors on these motors. Moreover I really like the 1200cfm tunnel ram fuel injected manifolds for these motors. Unless you have money to burn I wouldn`t buy new heads. If you just have to unbolt them,,,,well send them out for port work, mild chamber work and you`ll have the 502hp motor.

[victorfb]

hey hoss.....
do you mean to run the stock heads on this motor, or the 502/502HP motor. mine is the truck retrofit 502. it has smaller valved heads. the bottom end is the same except for cam specs, but still roller. that will definatly be changed but would like to stay roller style. and yes i would have to agree with the porting. its amazing how much potential comes from a good port job. thats a givin on whichever heads ill run.

[cyclone]

victor-dennis is correct about the heads being the same. I figured you might be able to save a few bucks since the gm heads dont say "edelbrock" on them. lol

[victorfb]

yea, to be honest with yaz, i wouldnt give a rats butt which heads i ran. either one would be fine. heck i wouldnt care if they said "amc pacer" on em. the unfortunate thing is that i have the cast iron smaller valved heads. its not the 502/502 nor the 502 HO, its the 502 retro truck motor that is a legal swap for 90-92 454 tbi motors. the bottom end is the same as the 502's with higher HP except for the cam size. id even run these heads if i had to, just do some porting to em. but then the cam decision would be a total guess. if anyone out there has some GM 502 aluminium heads they want to get rid of, im all over it. but to buy em from GM would be alot more $$$ than what i can get the edelbrocks for.

[Danhercules]

victorfb:
i realize i need to replace the cam, and will most likely get a set of edelbrock marine heads, (anyone use them?) i can get a smokin deal.
ive read on a motor building site about ordering your 502 with marine pistons and rings, what the heck does that mean? theres a differance?
I am waitin for a answer. What is the diffrence between "marine" motor and a "truck" or "car" motor.

[jstwkd]

Victorfb, I used the exact same motor. I went with the edelbrock heads 6045,and comp cams xr308hr 575 lift . I did switch the pan and head gaskets to a marine set up.
The motor needs alot of fuel. I ran a hp 950 on a tunnel ram and would suck the carb dry faster than the pump could fill it( hooley black pump). I left the stock fittings in the tank and a dual tank switch(gm came with the boat) and -6 lines big mistake. I switched to a cp performance mechanical switch a huge fuel filter and -8 lines. Problem solved.
The only other problems I had were the stock oil pump has 40 psi bypass so press. wouldnt make much over that even at wide open throttle. We shimmed up the spring for more press.
I have a gen 6 block The lifter bores are somewhat taller and the aftermarket lifters dont fit very well. The bar that attaches them deppending on the block has about .001/.002 clearance. The stock lifter set up is good until 5800 RPM.
If interested I am selling my Complete cam kit it has about 4 hours on everything . I want to switch to a solid lifter set up.Trying to get 700 HP out of it
You can determan the gen of block by looking at the timing cover. Gen 6 has only 6 bolts. Looks completly diff from a gen 4.Gen 5 is different also but I dont remember what exactly it looked like. Again its the cover.