[NAUBandit]

Hey all,

first thread here.

Basically I'm building a high-rev (for a Pontiac) 400 bored out to 4.25 with a stock 3.75 stroke and 6.8 rods on either the IA-II block or the MR1 block.

My main reason for this is the rod to stroke ratio to help the internals handle the high 6 low 7 rpms I'm looking for. Hence why I'm not using a stroker kit but want, again reliability where I can get it, and hence the aftermarket block.

My concept is an engine that'll win me the coveted "Red Hat" at Bonneville and get me into the 200 mph club with my dream car, a 1979 Pontiac Trans Am.

The rest of the drivetrain for this is all figured out:
TKO-T56 6 speed with stock viper gear ratio capable of 700plus horsepower
Shortened custom aluminum driveshaft
3.73 rear final gears in a 9" - using the 9" so I can gearswap when I need to for the other tracks I'll want to run on
295/50/ZR17s.

Now according to my math, I should in perfect conditions etc, with that gear range hit 228mph which should be enough, if it isn't I'll drop the final gear ratio.

My question now for the engine is this:
Naturally aspirated with high rev, high pump gas compression (10:1)
or can I get away with-
centrifugal supercharged (don't want the expenses of the custom headers for turbos), that can reach that rpm area?

I like the lower compression, lower ramp cam, and overall driveability of a supercharged engine putting out the power I want rather than a high-comp bruiser. At idle it handles nicer, sounds quieter, and is all around a bit of a sleeper until that supercharger spools up.

I'm just wondering if a supercharger can handle this.

Also, just as a final note, this car is being built to honor my friends, some of which I have been graced with knowing since kindergarten that weren't as fortunate getting home as I was. I'm an Iraq vet, medically discharged, and at least I made it back in one piece. They didn't. Most came home with a flag overhead and me playing TAPs.

This is for them. Also the car, whatever it may garner, or earn, will all be donated to the Wounded Warrior Project. They got me and some of my friends walking again, it's the least I can do, since I'm not allowed to go back.

Thanks for your help

God Bless

Pat

[techinspector1]

7000 rpm's with a final drive of 2.55 driving a 28" tire will yield 229 mph. This would be using a 4.11 gearset in the third member and 6th gear (0.62) in the transmission.

Oh, and Pat, thanks for serving.

[cobalt327]

As you get further into this venture, you will undoubtedly come across a lot of good info. One thing I would add at this point, is that wide tires aren't the "hot set-up" for salt flats racing- the wider tires can actually cost traction by hydroplaning instead of aiding it.

IIRC, "Z" rated tires are only good to 168 MPH

Good luck!

[NAUBandit]

thanks for the advice. Basically, that tire is my "do all" tire for SCCA and such. I'd probably go to whichever tire the guys that are veteran on the salts run when I get there. I actually hear the stock sized 235s run nice, so I may run that.

Really? A 4.11 rear gear with the 6 speed can hit that high?! Biggest problem there will be keeping her from sliding 1st gear through 3rd!

It was hilarious talking to some guys about my cam wishes. They were like "Pontiacs make torque, why in Heaven's name do you want 7,000 rpm with a cam and intake that kicks in a 3,000?!"

I replied that Pontiacs make great torque period, but when running circuit, I don't want power as soon as I'm off the clutch, coming out of a corner, all I'd do is go in circles!

after that, and seeing the top speed with the 6 speed, all of a sudden I got delusions of grandeur about earning a red hat.

so here I am.

but any help between NA and Supercharged? I know I'll change classes, but I'm not going for records, just the hat, and some fun.

Thanks for the assist

[WDCreech]

NAUBandit, Your biggest concern spinning a Pontiac for extended periods is going to be your oiling system. The stock type gear to gear oil pump just doesn't have the volume to do the job satisfactorly. I have two Pontiac engines and after years of running stock type pumps and bearing failures, I have switched to a Titan pump on my 474 (4.25" stroke) and a Peterson dry sump on my 606, (5.00" stroke) which sees over 8000 rpm, but I have GMP aluminum rods and light weight JE pistons. With over 150 passes on the 474, the bearings were near perfect, but it only turn about 7600. Remember to pay close attention to detail when you build your engine.

Bill