GPM

The intake is fine, just ran a similar one on the dyno worked well up to 6200. Your carb is smaller than what we ran to make 540 hp. I believe the dome on the Wiseco piston was about .100, would put you around 9:1 with a 118 cc head.

mike tkach

iTrader: (3)

rob,i will bet you will make more than 600 hp by accident.will you be running it on a dyno?

mike tkach

iTrader: (3)

if you go with 9.5-1 cr,a crane 731 hyd roller cam and a 850 carb you will break 500 hp,i do agree your 750 is to small and will restrict you.if in fact you do have the rhs 320,now the engine quest 320,i think you will be happy.

pjv911

You don't think 9.5:1 is too high with cast iron heads? Yes I have the RHS heads with 320cc runners. What is engine quest? The company that bought RHS?
As for the cam I will take a look at the specs. I would have thought that to be a blower spec cam since thats what Rob is using with a supercharger. Also ideally I would like to be able to use my existing valvetrain (except maybe a spring upgrade)

mike tkach

iTrader: (3)

9.5-1 is not to high,merc used lower compression ratio so their engine will run on 87 oct fuel,with 9.5-1 you will need 89 or better.from what i understand engine quest bought the rites to that head from rhs,it is a decent head right out of the box.imo it is a little big for a 454 but it still works well.edit in,the 731 is not a blower specific cam,it works great n/a also.

pjv911

Should I run a thermostat with this engine?
I was thinking without one it will be much easier to flush out the salt water once done for the day.
Also if I change pistons to increase compression should I be concerned with balance? Then comes the question of do I buy rods so I can also get floating pins and ARP rod bolts?
Im not trying to spend money I don't have to. Im just trying to get the best bang for the buck while having it reliable. Spinning the engine at 6k rpm in a boat can happen for longer than a drag car would.
Or maybe I should shoot for a lower (say 5500) rpm max? Or are the stock forged rods and 7/16" bolts up top that task?

dereknkathy

look for a set of pistons-rods from somebody who took apart their 454 mag to build a 496 with bigger crank. they are already balanced for that steel crank at reasonable rpm's. budget method of getting around 9.0 cr with forged pistons. those stock rods will handle what you wanna do with that motor.

midwest272

Are you planning on reusing the valve train you have ? The springs , lifters ,etc. will only work to a point with a more aggressive cam

pjv911

Is going up from 8.6cr worth the effort? I've read that one point on cr is worth only 20-25hp and then I won't be able to use any (away from home) pump gas. Of course I can get 92-93 at any station when on the trailer but if I go to Conneticut or Rhode Island I may not be so lucky. My tank only holds 60 gallons

pjv911

I would prefer to stay with the original valve train since it's about $1000 extra to upgrade that stuff.
It's my understanding that the 385 mag cam I have is kinda good already but considering I have dry aftermarket exhaust I'm interested to make the most of it.
So the question is how much cam can work with my stock roller setup?
Is it foolish to stick with the stock cam? Will this crane 731 cam work with the stock valve train?
Maybe just a spring upgrade?
Btw my heads are already done and assembled. And I have non adjustable rockers.
I can install the 3/8/ to 7/16 rocker studs if needed. I'm already thinking that will be a nessesity.
Also thinking roller rockers.