LT5 race engine

[SAM/CH ZR-1]

ZR-1 gang

I've got a question. Many years ago were some race engine build. I mean those which rev. up to >8'500 rpms.

Does anybody have some data sheets, performance numbers and pictures of these engines? I'd like to know with what cam specs, displacement, compression ratio etc. these LT5's did run.

Sam

[LGAFF]

all I know is that they were solid lifter motors and the engine failed prior to the Silver State Classic....

[SAM/CH ZR-1]

Originally Posted by LGAFF

all I know is that they were solid lifter motors and the engine failed prior to the Silver State Classic....

Thanks
Some performance numbers would be very interesting to see. If I am not mistaken they did have a 180 degrees crank, didn't they?
Every information about these engines is very wellcome. Especially the specs.

The reason for my request is we are going to build up a race LT5 for a racing team and look for components to get the most possible performance output. The first draw we've build is running with individual runners and pulls with stock cams about 550 crank HP by 7'500 rpm.

For the race season 2015 we want to increase the performance as much as possible. The same about revolutions. +9'000 rpms is the goal. Did anybody ever try cams with a 255 duration and a 0.500 lift?

Sam

[tpepmeie]

Originally Posted by SAM/CH ZR-1

Did anybody ever try cams with a 255 duration and a 0.500 lift?

Sam

Yes, that's what's in my 427. Not big enough. I need +20 degrees, and +.030" lift to breathe >7000 rpm. BUT, that's with a 4" stroke. Your mileage may vary. What stroke are you running, and what rpm do you want to make peak power?

[SAM/CH ZR-1]

Originally Posted by tpepmeie

Yes, that's what's in my 427. Not big enough. I need +20 degrees, and +.030" lift to breathe >7000 rpm. BUT, that's with a 4" stroke. Your mileage may vary. What stroke are you running, and what rpm do you want to make peak power?

Hi Todd
Theoreticaly we could go according the racing rules up to 545 cui. But then we would have to put additional weight into the race car.
Another point is the piston speed. With a 4 inch stroke or bigger it's hardly possible to go up to 9'000 rpm's.

So we think to go with a 4.075 bore and a offset grind stock crank with a 3.85 stroke. The power peak we hope to get somewhere in the 8'500 - 8'800 rpm range.

About mileage and idling we don't care much. What count is the power output with a useful torque band.

At the moment we drive with the 350 cui motor with ported heads and stock cams and 2 manifolds with individual runners. The LT5 like very very much to breath with the runners.

We look for the ideal cam combination and many other components to make the engine turn high.

Sam

[rkreigh]

Lotus had the rear engine car that was a flat plane crank engine with a velocity stack type intake that I believe was up over 750 hp and revved to 8500

not sure what the stroke or all the mods to the valve train (likely solid lifters)

Graham,

you out there?? he would know about this setup