pipes

Good morning all. So I have 1987 convincor and I am putting together a engine for it. I was going to do a 450 hp bbc for it. On my 450 hp build I was going to use ported oval port bbc heads. I now have access to Brodix heads. They are alluminum with 2.25/1.88 valves. 300cc intake runners and 132 exhaust. I know there will be a huge weight savings, but I am concerned about losing to much bottom end with having such large intake runners. But I think I can compensate for that because I am using a predator carb set up for marine. Let me know what you think. The heads are practically being givin to me so I would like to use them.

ezstriper

300 intake runners should be fine, what cu in ? exhaust ? also hase the drive been changed to a bravo ? most of those were alpha's..a few were TRS...never heard anybody running that carb on a boat...

MILD THUNDER

iTrader: (3)

The brodix will do much better than some GM oval castings. If, and I say if, you lose any power down low, you'll gain in the upper RPM band. Why the "predator" carb? A standard Holley 750 will work just fine. So would a quadrajet at 450HP actually. Will you be drag racing this boat from 0-70? If not, who cares if you lose 20ft lbs at 1800RPM. The only time my engines see 1200-3000RPM, is when im getting on plane, or getting off plane. The other 99 percent of the time, they are at idle or 3000-6000.

. What size engine you working with ??? What drive, etc. Like ezstriper said....

pipes

This is a fresh 454 with a stock bore and stroke. I was going to run a predator possibly because I have run them on my pulling/mud trucks with great success and better fuel consumption. They are a great torque carb with the variable venture. I know a lot of people bad mouth them but hat is due to hem not understanding how to adjust them. My original build was going to be stock bore and stroke with ported peanut ports with 2.19/1.88 valves and 234cc intake runners along with a edelbrock performer intake. A comp cams xtreme 262H-12 Lift .505/.515 and dur @ .050 218/224. I already have all this stuff and just happened to stumble upon the brodix heads. I just wanted a nice torquie engine without breaking the bank. If I run the brodix heads I will probably have to change up my cam and intake selection. What do you guys think

ezstriper

are you running in any salt water ? if so I would not run any aluminum head...

pipes

No It will not see salt water> It will be a fresh water boat only

motor

iTrader: (3)

What compression will you be running. I would probably go with a little more cam with the Brodies

pipes

It will have 8.5-1 for compression with either set of heads. My only concern was losing to much velocity on the intake runners. how much more cam, I am keeping the stock merc. ex manifilods. I don't want to have any reversion problems either.

motor

iTrader: (3)

I'm not saying a lot more cam .Maybe something along the lines of the comp XM270 226/[email protected]. 112LS I'm sure more will chime in with what they think .Or maybe call Bob M "cam guy".That 262 is a little cam and the brody heads could use more... I like the Edelbrock RPM airgap intakes on moderate motors ...JMO

Budman II

iTrader: (1)

I would stay with a more conservative cam profile, both from a reversion standpoint and also to keep the dynamic compression ratio a bit higher with that 8.5:1 CR. If you go with more cam, then you really need to find a way to up that ratio a little bit to take advantage of it - mill heads, thinner gasket, etc.

Also, with a 4.250 bore, you might want to consider notching the bores with those 2.25" intake valves, otherwise you might have some valve shrouding issues. 2.19 would be more optimal on valve size for that bore, IMO.