502 upgrade plan.....opintions??
 

I just bought a 98 velocity 280 and I'm going to pull the motor next week to start the rebuild. I'm trying to decide if I'm goin to build a n/a motor or a supercharged setup. My goal is 600hp. The boat has a 502 mag with Gil exhaust. I plan to use rods and crank if they are in good shape. I think finding a used 6-71, b&m 250 etc would be the cheaper way to meet my goal, but I don't want to put a scoop on the engine hatch to clear the blower. Other option is keep the efi and run a procharger m-3 to keep hatch clearance. If I stay n/a I plan on using a 850 Holley and dart intake that I have. Then go with a set of afr 305 heads and a custom cam.


Looking for opinions. Looking for the most cost effective way to reach my goal yet keep reliability.

Thanks in advanced.

if you want to stay na,go with a10 to 1piston,the heads you spoke of,and a crane 139651 cam,and 600 hp is minimum you will see.

oops.i noticed your engine is a gen 6,so the 651 cam wont work,you could use a hp 500 efi cam,or call bob madera for a custom cam.

I'm thinking about trying to reuse the 088 heads right now unless I come across a deal on a set of alum heads. I'm going to do bowl work, port match the intake and heads gaskets also work on the short radius in the exhaust port.

Reason I may try to reuse the heads I have right now are because I want to put hydraulic steering on the boat while doing the motor. So I'm trying to budget for the steering and that basically takes the heads out.

I've been told 600hp is still doable with the 088 heads if they are worked on a bit. Is this correct?

A buddy of mine, had a 509, with Merlin Rect port iron heads, crane 741 Cam, CMI headers, dart single plane intake, holley 800 carb. Did 605HP@5600.

Youll be pleasantly surprised!!

I'm hoping to be surprised. Lol

I don't know so I'm going to ask. Are the Merlin heads similar to my factory 502 mag heads (088 I think). I will be doing some work on them to help them out.


Thanks for the help!

Would that 741 cam be ok with my gill exhaust? I was planning on a custom cam, but if the 741 is good...

Will the factory lifters work with the 741?

i like the aluminum head because you can run more compression,and a little more timing,that coralates to more power,if you stay with iorn heads,i recomend a max of 9 to 1 compression.

Call Bob Madera tell him what you want and he will make it happen. I just bought a 548 that he had spec'd. AFR 305 heads his cam, its running 9.4:1 and on a conservative tune it is putting down 650hp/674tq.

It wouldnt take too much NA to get that motor to 600hp.

That's real good power for sure!