T/ALT1

iTrader: (3)

Ok, I have a customer wanting us to build a 427 super charged power plant for his 1977 Jeep. The Jeep currently has a 383ci SBC, Procharged @17psi. He wants more HP and the stock block is his current limitation. I have never built or done a LS7 build so I am asking for opinions and real world input on what would be a good plan for this setup. Customer would like 1,000HP reliably and he has zero LS parts for this build. I am thinking about buying a longblock and then just adding cam, headstuds, injectors, Holley EFI etc.. It will have a Th400 and 3000-3500 custom converter, currently has built 9' with 3.70 gears and 35" tires. It has 4 link front and rear and is just a 2wd street toy. This is what Im thinking so far...

427 7.0
Whipple blower
120# injectors
Holley EFI system
Blower cam/springs
Headstuds
accessories
Upgrade fuel system

jimmyg

Better off going with an lsx 427 . Probably cheaper, definitely stronger.

gsteele

Have little experience related to your question but would love to see pics of your customer's suspension setup.

stevieturbo

For the torque a 427 Whipple would produce, the iron LSX block would be the most sensible route.

You could use about any head/cam package you wanted and it will easily make big power.

http://www.thompsonmotorsports.net/i..._31_33_440_502

Or are you looking to do it on the cheap ?

T/ALT1

iTrader: (3)

After pricing everything needed to do a 427 I think it may be more feasible to do a 390ci setup using a 6.0 block and a 3.8" stroke crank. I dont think he realized how much a 1,000HP Blown setup costs, about $30k! So I think we will shoot for 850-900Hp LQ based setup which will be a lot cheaper.

stevieturbo

Make life simple....use stock stroke. Once you go 3.8" nobody makes off the shelf parts.

Get good heads and either go ARP625 studs or upgrade to 1/2" studs.

gsteele

Now that you are in the 850-900 HP range I would think that the LSX 376 B15 for around $8100.00 would be an option.

helicoil

iTrader: (104)

Not a cheap build. Using a 2.9l or 4.0l.?

http://borowskirace.com/Hellfire4L.html

Blown06

iTrader: (32)

Seems like that 4.0 Whipple is a bad bitch!

Blown06

iTrader: (32)

Is there a cog set up out there for the whipple stuff?

cajundragger

iTrader: (2)

If you go COG you'll need some sort of release valve in the lower intake incase the motor sneezes.

I think a multi-rib serp is fine for simplicity.

T/ALT1

iTrader: (3)

Going to use the 4.0L blower, that engine from Borowski doesnt look like a bad deal to me.

Blown06

iTrader: (32)

Is slip not as bad of an issue on the whipples as it is on the procharged stuff?

sorry for the dumb questions. I'm a procharger guy.

jimmyg

I run 10 lbs. whipple 2.9 with the stock 6 rib set up for camaro. No slip. I'm sure a 10 rib set up would work great

stevieturbo

I think wrp/ethyl gave up on the Whipple because or slip or other issues ?

Whether the blower itself can be blamed, or the design and implementation of it...is harder to say. One way or another, as long as you have room, you should be able to build a setup that does not slip. It may take 10, 12, 14 ribs, cog or whatever...but it can be done.

ZNix

iTrader: (1)

The Borowski motor looks like a good deal to me. I don't think you could build it for that much...

helicoil

iTrader: (104)

GM's COPO Camaro race cars with the 350SC have zero problems with the 10rib 2.9L Whipple's maxxed out. Will run 8.70's 1/4 mile over and over and over.

It is a nice, low maintenance set up that packages really well. For some reason they (GM) killed the Whipple 4.0L in 2012/13 on the COPO program. Borowski has said their 2.9L set ups do just fine on the 8 rib - no slip.

The 4.0L and 4.5L may be different. I would stick with a serp set up for a street/strip car.

jimmyg

Mast motorsports has an ls3 based 427/whipple 2.9 . 917 hp on pump gas.they call it little big man.

gametech

iTrader: (1)

Slip is a matter of pulley sizing and configuration. On the sort of completely custom setup the OP is looking into, this should be sorted before the build is even started. I'm guessing in your case you are trying to get more boost than the factory "kit" was designed for. I know my comment doesn't really answer you question, but it seemed relevant.