Yea. . . WAY low, especially if you want SBC heads equivalent to LS7 heads. Then you're talking $20k+.

 

What?!?

Again... What?!? What makes you think it would be cheaper to build a 427 LT1 than buy an LS7?

Mike

 

This would not be an "LT" anything!! And he wants an LT 427.

 

You've had your question answered. You sleeve an LT block to get a 4.125" bore and stock it to 4.00". Then you work out the cam/heads/intake.

I definitely think you should do this! Hell, it's only money. When you've reached $15,000 post back and let us know how it's going!!!

 

lol @ this guy, his dads home ported heads with stock valves on a 388 made 500hp? your dad need to go talk to lloyd and afr tfs ect, because he be making some big money....
a 400+ cubic inch lt1 is a waste without afr heads or sb 2.2, put an lsx in it and save alot of money.....

 

If you ask me its not smart. Look what you have to wrok with....who ever posted you can go to a 4.090 bore is crazy.

Even if you do build(and 20K is low) it won't last long...not in a LT block......you have to take alot of meat out for all of that.

I know someone that tried to build a 400+ inch LT motor....3 blocks later he just went back to a 388...did some more headwork and impressed all of his "FANS".....and I think he was only trying to do 411 inch motor

 

500 at the crank on an engine dyno is not that much AI, LE and others deliver that every day. Once restricted by in car intake and exhaust accessories and drivetrain losses that is well under 400rwhp through an A4.

Far as making a 427 LT1, there is an Impala guy with a 434 "LT1" started with a Donovan aluminum block and machined it for everything that seperates an LT1 from a Gen 1. He has AFR 227s modified LT1 intake, stock WP and stock opti, hydraulic roller cam and a blower best run sofar is like 9.6 at 146mph 4400lbs raceweight. He has been invited to the Pump Gas Drags again this year so look for magazine coverage on the car. Oh yeah 4L60E and 8.5" 10 bolt too which is what these came with.

 

There was a guy who used to post here about 5 years ago that built two different versions of a 421ci LT1. He had the dyno charts, photos and full specs available. Ultimate life of the engine was never revealed.

4.090" bore x 4.000" stroke
4.030" bore x 4.125" stroke

The 4.090" bore was done on a block selected for its sonically tested wall thicknesses, and the bores were recentered to put the meat on the thrust side. It made some fairly decent HP (750+) with a decent shot of nitrous.

Ultimately, he failed to deliver on his promises on some fairly radical engines he had promised to board members, and disappeared

 

If you want to throw away your hard earned money... just send it to me... and I promise to spend my time getting drunk and partying with it.

 

Only if you invite us Heatmaker.

 

First I would start with one of the 20 or so race blocks based off the bowtie's
They go 4.155 no problem. Look for casting 202A

 

shouldnt it be possible? i mean most car enthusiast dont even know what the numbers mean: 302, 350, 454, 440, 502, etc, its all bore sizes. I'm a cnc machinist and I'm trying to find a way to bore out the biggest size possible, without changing every freaking thing under the hood. bigger bore is a bigbig power gain. I kinda just learned about the whole engine numbers thing, always wondered why there were bigger numbered small blocks that are bigger in size than bigblocks. it should be possible so long as your car can handle it?

 

If your a CNC machinist..what do you machine? If you understand how a block is cast and what you have to work with......it's simple

The other thing alot of you guys posting don't under stand that when you push things to the limits like this your riding on barrowed time....So why not do it right to begin with


My friend bought a $21,000 engine last year for his 69 camaro....one of 3 motors he owns, This was a 454 SBC.....it lasted 2 weeks B/C he tried to cut corners....car made 814 at the wheels and he got 10 passes out of it.....now if he would have spent a little extra and gotten a better block.....the 454sbc would still be here with us. Trying to do it with an LT1 is just stupid the way I see it......seems like you want to prove it can be done more than you want the power .......and this will just make you broke, I talked to a few people yesterday.....when I asked if it could be done for less than 20K they laughed at me and said why even bother.

You can buy a 1100 h.p. BBC turn key for 17,000

 

Good post Mike.

 

Big bore is not a big power gain, if it causes the cylinder walls to be so thin they can't contain the pressure generated by the combustion process. Or deform under the thrust loads of the pistons. Everyone has sort of explained that you aren't going to be able to go much past 0.090" over with an LT1 block, and even that will take a "select" block. That's less than a 5% increase in the area of the cylinder. How does that make "big power"? We've suggested that sleeving is a way to go, but that has been completely ignored.

Or you might want to try a "search" on the "Advanced Tech" forum. I remember a couple years ago some guy from Saudi Arabia ridiculed all of us who recommended limiting the overbore to 0.060", claiming that they routinely bored LT1's to 4.120" and made huge HP..... sounds like someone you need to track down, since he's obviously a lot smarter than all of us.