MILD THUNDER

iTrader: (3)

I know a 502 with 360cc heads is a bad choice. But, is it really that much worse than a 454 with 325 cc heads that flow like crap? Because that's what GM/merc used for decades. Ideal ? No.

Dominator carb, yea a bit too much. But really any worse than a 800cfm quadrajet on a 330hp 454 ?

I guess what I was trying to get at, was even though the parts he has are far from ideal, I wouldn't throw the engine in the trash bin and leave the boat in storage until he can perform an ideal build. I think by shrinking his cam choice and changing exhaust he could be tooling around the lake for the interim. Just my opinion.

I'm guessing the "360" heads he has are the Dart "race" series castings. Pretty nice heads, and if he wanted to keep them he can have a guy like valako wedge the ports like he used to do with the gm square ports on marine setups.

SB

iTrader: (1)

My experience. When someone mentions 320 or 360 with no reference to the company they are usually chinese Procomps.

If someone has Brodix, AFR, Dart, or even Edelbrock's, they mention it.

Anyway, we all agree, the exhaust is first, then cam, then heads, then carb.

Ah screw it, put it in a v drive or jet boat and start over for the I/O.

SB

iTrader: (1)

MT - I totally understand what you are saying. I've tried to do the same you are with many people over the years. It doesn't really help them. In fact, it usually hurts them. Even thoy it feels like you are trying to help.

I
That big carb will suck with a small cam.

General rule of thumb I've come up with. 650 or more HP, then it's Do time. Engine will like it. Under that, the carb will be out of it's elemnt and pretty much suck azz.

The one part that will get him back on the water - dry exhaust with thru transom water dumps.

Walzee

Thanks to all the responses, Mild thunder I appreciate your input and advice, seems like you understand my situation, and nice avatar pic!! I think if I was to listen to SB I should not go anywhere near the water, lol! I realize this combination is probably not the best suited for this boat, my goal was to do some boating, my last boat had zero cool factor and was quite boring, I knew if I listed the head size and carb it would open a can of worms, I mentioned that in hopes of getting across that with larger port sizes port velocity would be way down and should help with reversion, these are brodix heads with jesel rockers, way overkill, but I have them, and they are nice pieces, carb size also was mentioned, yes its a big carb, but what is worse? a 800 cfm on a 330 hp engine? I put this carb on my s/g car, its a 377 small block, it ran within a tenth of the best 4150 style carb, it idles great, and has great throttle response, would a smaller carb work better under 4000rpm, most likely, but I have this one and it was expensive, I do not think anyone has lifted their hatch and someone said "Hey nice Quadrajet" although I ran one on my NHRA stock eliminator car and if you spend about 1k on them they work real well, I ran 2 1150 dominators on a 458 cu in engine in my comp eliminator car, it made 1185 hp on gas, so I am aware of proper combinations and buying good parts, but my question was about water in the exhaust, I did not realize these manifolds were that inefficient, thanks for the education, but this boat has 290 hrs on it with this setup with a big block in it so it worked for some time, so ill change the camshaft, the 502 cu in really shouldn't be an issue, it will start and get me around, we only have a couple months of possible boating time around here so I will change exhaust around this winter, mike tkach, I would be interested in one of those cams :-)

SB

iTrader: (1)

I have to answer it that way, because if I don't, the person ends up blaming me and others when things don't work the way they dreamed.

That's why.

You know the deal.

FIXX

iTrader: (2)

try advancing your cam 4* and see what that does for you.. or to be honest theirs a set of stelling headers for under a grand on the swap shop and it might be cheaper to put the exhaust on instead of changing the cam which is a roller and you will need retrofit lifters..sounds like it could be a mean mid and high rpm cam..

mike tkach

iTrader: (3)

i can fix you up with the hp500 efi cam and a set of retrofit hyd roller lifters for a fair price and i garantee the parts are good.pm me if interested.i really think a stock 415 horse 502 hyd roller cam would be the way to go with the stock merc manifolds,no chance of reversion and you will be boating!im sure someone on oso will have that cam for 100 bucks or less.