If you were to rebuild a 502, what would??

[Wally_Gator]

What would you do to it for 91 octane on a jet?
Trying to get some ideas for this core 502 I have..
Looking to build it to run mean, yet no Av gas...
What rods would you think of using?
This is a 2003 GM 502 out of a Chevy 3500 truck...
Ideas Please?
Thanks..

[disco_charger]

Search on here for Cyclone's 502 build up. He had a cam/head/single carb set up that was pretty amazing.

[sdba069]

We've had several rod failures with the crate 502's. I'd spend the money on a set of Eagle H-beams.

[flat broke]

Search on here for Cyclone's 502 build up. He had a cam/head/single carb set up that was pretty amazing.
Ditto that, I think mike ran AFR 335? heads, a well thought out roller setup, a touch more compression (from the chamber size on the heads not a piston change if I remember correctly) and was puttin out some VERY nice HP for the $$$. personally, I'd look into a set of CNC'd Canfields, but go along the same lines as what Mike did on the old single carb deal in his Rogers. The only difference would be that I believe he started with a ZZ502 (forged rotating assem and pistons made by JE for GM). You're truck internals might be a little different.
Good luck with it,
Chris

[Wally_Gator]

Thanks for all of the info...
I am planning on going .030 over and have already thought about rods.
Heads and cam and valve train is where I had the most questions..
Stock crank or?
This may find it's way into another Rogers or maybe?

[DeputyDawg]

How much power are you wanting to make? Do you mind running the valves every once in a while? I would run the CNC ported AFR 315s on a jet boat motor on a 502/509ci deal at about 10:5-11:1 comp. with a properly matched mech. roller, good roller rockers and stud girdles and a good set of rods that were prepped by someone who knows what they are doing. I am running the AFR CNC'd 335s on a bigger inch motor and I love them.

[dmontzsta]

If you are swapping from a Olds, you should just go with the blue oval and run a 514 on pump gas! :D

[SummitKarl]

What would you do to it for 91 octane on a jet?
Trying to get some ideas for this core 502 I have..
Looking to build it to run mean, yet no Av gas...
What rods would you think of using?
This is a 2003 GM 502 out of a Chevy 3500 truck...
Ideas Please?
Thanks..
there is really only one safe proven answer here (in my eyes)........TRICKFLOW KIT,
you get Arias pistions, eagle SP-Ibeam (bushed) rods, for the most part just top notch parts at a great bang for the buck. and you can run 91 all day long

[Wally_Gator]

If you are swapping from a Olds, you should just go with the blue oval and run a 514 on pump gas! :D
Couple of reasons fro NOT wanting to do that....
1. Parts availability....
2. Parts sources...
AND the Biggest reason....
I have been bit by the blue oval before... Never again...
Been there, done that... and it definately did not git r done...
So, how long for you? Maybe you should rig the donor so you have a ride at CBBB...

[dmontzsta]

Couple of reasons fro NOT wanting to do that....
1. Parts availability....
2. Parts sources...
AND the Biggest reason....
I have been bit by the blue oval before... Never again...
Been there, done that... and it definately did not git r done...
So, how long for you? Maybe you should rig the donor so you have a ride at CBBB...
The Donor is still a ways out, I am taking the time to put it together right, it has mostly new parts. When someone buys it I want them to have a solid boat that has been gone through. The reason I didnt rush to bring it to CBBB is because I dont want nothing to happen to it, I just want to sell it.
I dont know how long it will be for me. I am thinking 514 with a 8-71 blower now...who knows.
You have a good point about availability of parts, that chevy stuff is all over.

[Wally_Gator]

How much power are you wanting to make? Do you mind running the valves every once in a while? I would run the CNC ported AFR 315s on a jet boat motor on a 502/509ci deal at about 10:5-11:1 comp. with a properly matched mech. roller, good roller rockers and stud girdles and a good set of rods that were prepped by someone who knows what they are doing. I am running the AFR CNC'd 335s on a bigger inch motor and I love them.
My plan on HP was in th 500's ... Seems like that is a very easy target.
We will see what I can afford when I get to that point. I am working on the boating season right not. This is gonna be a fun winter project...

[dmontzsta]

My plan on HP was in th 500's ... Seems like that is a very easy target.
We will see what I can afford when I get to that point. I am working on the boating season right not. This is gonna be a fun winter project...
You should be able to get 500hp pretty easy with a mild 502 on pump gas. That sounds pretty easy to me.

[Wally_Gator]

You should be able to get 500hp pretty easy with a mild 502 on pump gas. That sounds pretty easy to me.
Based on Cyclone's 502.. I think I have ditched the 500's and am now looking to come close to duplicating his build this winter.

[Wally_Gator]

Thanks for all of the good info. I guess I may need to get another paper
route in order those AFR heads...

[jimthetoolman]

I have a set of brand new pistons for a 30 over 502 if your interested. (509 c.i) SRP forged Pistons. Let me know if you need them.
I just built a 502 in my jet and I am very happy with the outcome.

[Wally_Gator]

PM me with the price. I am still considering if I want to stroke the thing...
I am working on the complete plan and target...
Thanks..

[cyclone]

Wally- things to keep in mind with your block. Because of the siamese bores you cannot overbore it very far. I would keep the stock bore diameter because you can only squeeze about two rebuilds out of it. Off the top of my head i think a 509 displacement is the largest you can safely bore it to.
I'm unsure if your motor has the forged bottom end or not but here's a few things to consider. If you plan on beating on the motor hard and keeping it i would spring for a new set of rods or have bushings installed in the ones you've got already. the stock gm forged crank is good to 800hp. Definately replace the stock rod bolts and head bolts. You can easily make 500 hp with stock gmpp aluminum heads and a cam change. Should you decide to make more power then better heads, cam, intake carb will get you over 700 fairly easily. My ZZ502 made 530hp out of the crate with the stock parts.

[Wally_Gator]

Wally- things to keep in mind with your block. Because of the siamese bores you cannot overbore it very far. I would keep the stock bore diameter because you can only squeeze about two rebuilds out of it. Off the top of my head i think a 509 displacement is the largest you can safely bore it to.
I'm unsure if your motor has the forged bottom end or not but here's a few things to consider. If you plan on beating on the motor hard and keeping it i would spring for a new set of rods or have bushings installed in the ones you've got already. the stock gm forged crank is good to 800hp. Definately replace the stock rod bolts and head bolts. You can easily make 500 hp with stock gmpp aluminum heads and a cam change. Should you decide to make more power then better heads, cam, intake carb will get you over 700 fairly easily. My ZZ502 made 530hp out of the crate with the stock parts.
Thanks...
My initial thoughts have been (before this thread):
1. New rods.
2. New fasteners... Head studs maybe...
3 New crank? Not sure but thinking about it...
4. Stroke the motor? Maybe?....
5. Pistons.
6. Cam and roller rockers...
Then everyone mentioned your buildup...
That really got me thinking about the AFR heads... (I hate everyone of you)
Now I really have to pony up the $$... I am looking for a respectable motor that will be reliable.
So what would you have done different?
Other than changing your distributor gear?
What temp did you run at?
Thanks ...
Walter