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Budman II 09-15-2016 02:51 PM

Yep, if my wife found out how much my last build cost, she would be making the shoe store and the furniture store very happy!

Budman II 09-15-2016 02:52 PM

Would he be able to make it to 600 with a set of AFR 265's and some Lightnings? The smaller chamber of the 265 would bump up the compression. I might actually be tearing into mine this fall, and if so, ya never know, might be a set of low hour ones going up for sale.

mike tkach 09-15-2016 04:03 PM


Originally Posted by Budman II (Post 4481739)
Would he be able to make it to 600 with a set of AFR 265's and some Lightnings? The smaller chamber of the 265 would bump up the compression. I might actually be tearing into mine this fall, and if so, ya never know, might be a set of low hour ones going up for sale.

i might be interested in the 265s,let me know if you decide to sell them.

getrdunn 09-15-2016 04:13 PM

Definitely some smaller chamber heads would be ideal to bump the compression and make some good power gains at the same time. he'd really have to do some under the radar back alley trunk deal on those heads though. What chamber size are the oval 300's? List goes on. Then intake etc. $$$.

MILD THUNDER 09-15-2016 07:47 PM

Assuming you have a dished piston, most "Dished" pistons in a bbc, are typically a -20cc dish. In a 502, with 119cc heads, you'd be looking at a static around 7.5:1 roughly. If you were to install say a 110cc chamber head on them, you'd be bumping it to a whopping 8:1.

If you're looking to build a decent pump gas engine combo, it sounds to me, like you're gonna need to change out those pistons.

getrdunn 09-15-2016 08:06 PM


Originally Posted by MILD THUNDER (Post 4481809)
Assuming you have a dished piston, most "Dished" pistons in a bbc, are typically a -20cc dish. In a 502, with 119cc heads, you'd be looking at a static around 7.5:1 roughly. If you were to install say a 110cc chamber head on them, you'd be bumping it to a whopping 8:1.

If you're looking to build a decent pump gas engine combo, it sounds to me, like you're gonna need to change out those pistons.

Your absolutely right. For some reason I was thinking stock Pistons. Looks like a complete tear down regardless so OP gonna need Pistons along with whatever else builder finds. OP might wanna just do a rebuild with some machine work and new Pistons and refresh existing heads. Get compression up and do the 731 or 741 cam to keep it simple. Crank and cylinders ok? 2,500-3,000 when said and done.

SB 09-15-2016 08:30 PM

Anybody see or even here of anyone running a dish in a 502 ?

Exactly.

I bet it doesn't.

We;ll see though,right.

cabin fever 09-15-2016 08:33 PM

Thanks guys. New pistons have already been ordered. I don't recall what he told me, but I believe it said it was a dome piston, and do remember he said compression would be between 9.25:1 -9.5:1. that was with him guessing, with the merlin heads (one of which is junk). So yea, the old pistons are not going back in. He did say my merlin heads had some pretty nice porting done to them, so he wanted to make sure we got something comparable to what I had.

I;m kinda surprised this motor ran as good as it did. One head had 2 different cracks (one of which had previously been repaired, which failed), the other crack ran through the head bolt area. The cam had a worn lobe.

block checked out ok, but he had concerns about piston to wall clearance, he said it would be over 7 thousandths, and wasn't keen on that. , Gen 4 bowtie block, with roller conversion. Block is getting bored .030. Crank polished.

600HP would get me solid 80mph GPS with this hull, at least it did with my 02 280.

cabin fever 09-15-2016 08:37 PM

He did say the motor looked like it was originally set up for a blower by the pistons, lower compression,, and cam grind. Which makes senses as the seller told me the boat originally had a blower, and he had it taken off. I'm guessing he literately unbolted the blower. I would have thought you would have to do some other tuning or something to make it run right, but the engine did run pretty good, I must admit. Had I never saw the oil psi issue, or cut open my filter I would have never known there was anything wrong with it.

I'll be talking to him tomorrow to figure out where to go from here. Just trying to do some homework in the mean time. Since I am gonna have to pony up for new heads, figure it kinda opened a door for a little more power.

getrdunn 09-15-2016 09:19 PM

600 is certainly achievable with a good head, cam, intake combo. Definitely plan on decent set of heads to get you there.


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