750hp turbo build

I don't know a lot about BBF's but apparently making 750 even N/A is a piece of cake so I'm happy the catamaran I just got has one! Boat is a Warlock 28 cat, 4000lbs.

I don't know a lot about what's in it now but here's what I do..

460 w blue thunder iron heads
stud girdles and crane gold roller rockers
demon carb
msd ignition
.....................and that's about it!! Tearing it down this winter so i'll know more later

My goal is 750 hp, with max rpm of 5500. I have a Gale banks TT system I'm gonna use, and it can be set at 5,9, or 11 psi.

I like the idea of the 547 or so Scat stroker kits but I want to keep the CR under 9:1 so I think the 4.5''kit is out. Another dilemma, I figured more cubes the better, especially in a boat where the RPM will be under 4000rpm 90% of the time, but with the turbos do I really need the cubes?

I want to go turbo bc I have it, and I like the low stress on the engine and gas (most the time)

OR

Am I just complicating things, and I should just do an easy 750 N/A ??

Sorry, I'm kinda all over the place, any help will be appreciated!!

^^ I agree with Dave^^

With turbos, you can make 500 fhp with 9.0 c.r. and a mild hydraulic flat tappet cam and 8-9 lbs of boost will get you your 750 hp....easy.

The only reason i was even thinking about the stroker was that the motors getting torn down anyways and just thought it's a cheap way to add 100 cu.in. (i saw one for $1200.00)

but.....these are the tips I need. No more stroker.

I know Turbos do well with stock cams, but should I get a turbo grind instead? and what kind of cam specs should I be looking for?

Thanks again

Unless you can luck up the 6.605 h-beam rods cost a lot more than they should IMO. This is where the machine shop is going to suggest you just buy an aftermarket crankshaft. Instead of having the factory crankshaft ground to 2.2 rod journals.

I've been down this road before.

If you have someone local that can grind the crankshaft I see no reason why a set of Scat H-beams with Probe, KB, Mahle forged pistons wouldn't work (read no trws, speed pros). Just have to work out the off the shelf piston CH selection with how much the crank needs to be offset ground. Keeping CR in mind with your piston selection.

TRW, Speed Pro's just weigh too much and the ring package sucks IMO.

dfree383 wrote:I'd get a proper cam ground for it.

On the stroker stuff too, you need to watch the turbo sizing and the CID / RPM range they are intended for.

I agree, if you go to large you will come into all sorts of head aches. Then again I tried this deal with a 472cu, factory crankshaft, FRPP 6.605 rods and Speed pro pistons with a Borg Warner S400 (74mm 1.32 A/R). I just never could get comfortable with the combonation. I believe the 74mm will work if you just get the proper hot side. Rather than fooling with the standard hot side. Bullseye should be able to help you out with turbo sizing.

PS. I have a brand new custom soild flat tappet camshaft for this combonation I'd love to part ways with.

Edit: I missed the part where you had the Gale Banks TT kit! In that case it should work awsome! I wish I could have got my hands on one of those kits when I was trying my build.

jones wrote:
....PS. I have a brand new custom soild flat tappet camshaft for this combonation I'd love to part ways with.

You have a pm....

Just to give you an idea here is the numbers from a turbo camshaft I have. It was ground to idle smoother than stock yet spool-up the turbos. This camshaft was from Bob down at ?? Cammotion??

Solid Flat tappet

Duration 230/230
Lift .55122/.52138
Intake centerline 109.7
lobe sep 114.8
Overlap .9

Intake
VO 109.7 btdc
VC 45 atdc
Exhaust
VO 54.1 bbdc
VC -4.1 atdc

dfree383 wrote:I'd get a proper cam ground for it.

On the stroker stuff too, you need to watch the turbo sizing and the CID / RPM range they are intended for.

100% correct. I run a PT106 1.50ar with a G-trim wheel and it needs to be clipped down because of major back pressure issues. If you add ci then I'm willing to bet those turbos will run out of steam real quick. The minimum single that I would run on a 429ci engine would be a S480 just for comparison.

with the rpm he is talking about and the power output he wants, I would put the turbo kit on with the stock cam, 9-11psi, C&S or CSU carb and have fun.

whatbumper wrote:with the rpm he is talking about and the power output he wants, I would put the turbo kit on with the stock cam, 9-11psi, C&S or CSU carb and have fun.

Well it's not a stock cam right now, i don't know what it is, but def not stock, along with solid lifters

schmiddy wrote:

whatbumper wrote:with the rpm he is talking about and the power output he wants, I would put the turbo kit on with the stock cam, 9-11psi, C&S or CSU carb and have fun.

Well it's not a stock cam right now, i don't know what it is, but def not stock, along with solid lifters

Does it work well? If it does use it. If it doesn't spend $250-$500 to get another one ground.

If you are going to go blow thur go with a (CSU, or CS) carb and sell that BG carb. Just my .02$

Well unfortunately it's your typical Banks draw thru sytem w single holley 850, has anyone ever converted one of these to blow thru? I've thought about it, just need an aftermarket intercooler.

Also, i'd still like to run 1 carb, how much HP can a holley 850 dp support? What's the difference bt say a 1050 holley and the CS or CSU?

FYI, don't really like the demon, maybe it's just me not being used to it

schmiddy wrote:
Well unfortunately it's your typical Banks draw thru sytem w single holley 850, has anyone ever converted one of these to blow thru? I've thought about it, just need an aftermarket intercooler.

Also, i'd still like to run 1 carb, how much HP can a holley 850 dp support? What's the difference bt say a 1050 holley and the CS or CSU?

FYI, don't really like the demon, maybe it's just me not being used to it

I have seen over 2000hp with a 4150 carb in a blow through app. Your combo is NOT going to run out of carb with the setup you have in mind with an 850. To convert the banks system you can just get a carb bonnet from New Era Racecraft or one of the carb companies we have listed and build some new tubing to fit. You could run an intercooler but with the boost levels you are talking about and a pretty mild horsepower goal, I think you could save yourself some fabrication work and run it without one. And the C&S and CSU carbs are built for this type of app. That is why we recommended them over the plain holley. They might even be able to just modify your current carb.