johnnyoffshore

Rebuilding my old 454 (468). Block is being bored .100 over to a 475 cid. Block is a GM Bowtie 4-bolt main, tall deck, have just about all my parts, flat top pistons for 8:1 comp, LA Enterprise Kryptonite crank, Carrillo rods, Reher-Morrison Signature Series CNC Ported Brodix heads with little more custom porting (flowing a tick over 400 cfms), Crane Gold Race full roller rockers, The Blower Shop 10-71 Blower with nylatron and Teflon strips in rotors and The Blower Shop Intercooler, 2 Chuck Nuytten marine prepped blower 1050 dominators carbs, Weaver dry sump oiling system with Weaver pump and tank, MSD 7ML-2 & Pro Power Coil and MSD Marine Distributor, Jesel belt drive, etc. Want to make max horsepower at 5600-5800 RPM. Motor is set up to run solid/mechanical roller. Need advice on specs to be at that 5600-5800 rpm target.

Thanks,
Johnny

johnnyoffshore

To run on pump gas with about 8 to 10lbs of boost. Underdriving the blower.

Thanks again,
Johnny

johnnyoffshore

If someone could recommend a good electric fuel pump for this application, I would appreciate it.

Dave F

well, for off the shelf Crane cam you could look at the 138781. Its a 246/254 114 .615/.636 It would be managable (barely) around the dock on a 468 and the lift isn't so extreme that you're looking at valve spring problems.
As far as a fuel pump, Aeromotive or Product Engineering. Aero is a fairly straight forward, easy to use pump, The PE is a little more intense. It is the same design as the Magna pumps, but PE is the original.

DAVE

johnnyoffshore

Thanks Dave,

Would that cam make peak power below 6000 RPMs? Need to max power out around 5600-5800 RPMs.

Thanks again,
Johnny

johnnyoffshore

Nice HP gain with cam change only!

Thanks

johnnyoffshore

A boating buddy of mine told me that Crane Cams Part # 138551 would be a good choice for my 475 ci blower motor with max HP at lower RPMs. It has 238 int./246 exh. @.050 with 0.595 int./0.615 exh. lift. Its on a 112 Lobe Separation, told that was perfect for a blower motor. With a cruise RPM of 3400-3800 RPMs. Grind Number: SR-238/350-2S-12 IG. What do you think?

Jb-fse

for a fuel pump a s-x 18203 will work and is coast guard approved also a 15402 regulator is match to work well.

PatriYacht

Your part selection doesn't make sence to me. All of those high dollar parts and you only want to spin 5600-5800? You could do that with Eagle components, a 8-71 and a couple of 750 holleys. Even with a small cam, this engine will still be a pain to live with on a daily basis. A 600 ci short block is what you need to go with the rest of these parts.

johnnyoffshore

Well the motor was an A-Class motor in my race boat, which I am converting to a pleasure/poker run boat. The motor was 12.5:1 comp natural aspirated single dominator 850HP @ 7000 RPMs on CAM2. So I already had all those high dollar parts. I don’t want to stroke the motor because I already have that Kryptonite crank and those Carrillo rods. Since the block is a GM Bowtie block with thick walls, I can punch/bore it to a 475 CI, most CI without stroking it. I want to run as much HP as possible at the lowest RPM as possible to save parts, drive, gas, maintenance, etc. all on pump gas. I am on a tight budget now. I do not make the money I use to, needless to say. So I am trying to work with what I already have. Only had to buy pistons, blower, intercooler and one more carb. The rest I already had and they are in like new condition. That is the only reason I am doing it this way, I know the 475 CI is small and an odd number. I wish I could pony up to stroke the motor to a 632 or something. But I have what I have and now I make less then ever before with 2 kids thrown into the mix. Which is why the boat has not touched water in 4 years, but kids are just old enough (daughter 3 and son 2) to fit in life jackets safely and wife gave me the green light and a BUDGET! No questions ask, I ran to the machine shop with what I had, and gave them my budget and goals. This is where I am at, just need cam advise and fuel pump advice… Hopefully soon, Prop advice! But I think Throttle-Up has me covered there!