What would be involved in building an LT1 to rev (and actually produce power) lets say to 7500 RPM (With 7000 being the yellow and 8000 being the absolute limit)? I am going for top speed here, so any loss of the bottom end is acceptable. Or am I being too hopefull here?


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It can be done, but it won't be very cheap. Pretty much anything that is out of balance will greatly increase vibrations at higher RPMs, so you or the engine builder will be spending a lot of time with a scale.

Everything in the rotating assembly needs to be weighed and balanced. NASCAR and NHRA engine builders often times spend a couple hundred man-hours on assembling each engine, and those guys know what they are doing. They weigh every single thing in the rotating assembly to the 100th of a gram and very carefully balance all of the weights.

Your valve train will require a lot of attention as well. Stock valve springs won't work at those RPMs as they would be subject to valve float. Again, your entire valve train would need to be weighed and balanced.

All of your clearances and tolerances will have to be very close to perfect to allow the engine to last even a little time without grenading. NASCAR engines are torn down after every race, and pro NHRA racers tear down their engines between runs to check for anything that is even slightly out of specs.

You are not going to be able to get those types of RPMs out of your stock parts. You are going to have to go with forged everything. That won't be cheap by any stretch of the imagination.

You also will have to do a lot of work on the intake, injectors and exhaust. You will have to move a ton of air at those RPMs so even a slight restriction anywhere between the air filter to the muffler will cause your HP to suffer.

It can be done, and it can even be done in your garage. But it will require a lot of time and everything will need to be just about perfect.

 

I didn't build my motor, but it has saw 8800 rpm a couple of times, but the guy had $8000.00 in the motor...he says. So it can be done.

 

in order to produce hp at 8k your powerband will be narrow. probly 4 to 8k.

 

‪95 Camaro LT1 NA 10.37 @131‬‏ - YouTube

it can be done. btw, that's a 385ci stroker turning 8300rpm at each shift.

 

You really shouldn't be revving a 2 bolt block that much over 6k

 

the LT1 i posted is a 2 bolt block. he's had no trouble with it in around 350+ passes. a 2-bolt main block can be built up to be stronger than a 4-bolt main.

 

A "properly" built engine would have no problem operating at those RPMs. The Opti may not be too happy at that speed but it could be replaced by some sort of crank trigger device. Other stuff such as injection and valve train will have to be upgraded, but all that stuff is available. By properly built, I mean high quality materials, machining, and assembly.
Many moons ago I used to run an A gasser, supercharged 330 inch hemi, Enderle injectors, aluminum rods, billet main caps, and 20-25 lb blower boost. Shift points were at 8200 RPM. Impressive considering the size of the rocker arms in that engine. Just about everything in the car broke at one time or other, except the engine. Bearings would take a pounding, but that was expected, and were replaced before each meet.
Having said that, if you build the engine properly, 9000 RPM are feasible.

 

Correct me if I'm wrong but people fear the word two bolt main when combined with power
A light internally two bolt engine will spin whatever you desire and the valvetrain better be spot on and light because valve springs are gonna have some preload just to keep up with a solid roller cam of that caliber. Being a mustang guy those two bolt 302/351 do not like friction nor weight when running those kind of rpms plus these lt1 blocks have hella lot more meat where the ford motors fail not to mention main bearings doing the moon walk lol it can be done just gotta ask those who do it on a regular basis

 

Agreed. The hemi we used had 2 bolt mains and held up fine, and all we done was to change out the cast main caps with billet caps and align bored. To control the valve train we had a set of springs acting directly on the lifters, and another set in the stock position in the heads. This took a lot of strain off the push rods.