Possible to use conventional 400 block and build a 377ci LT1?
Possible to use conventional 400 block and build a 377ci LT1?
Is there any way to adapt the pieces together to work properly? Reason being is I have a VERY nice 377 just laying around and a worn out 94Z28.
Re: Possible to use conventional 400 block and build a 377ci LT1?
I don't think so. I would rather have a convential SBC just to get rid of the opti anyway. You can convert to reverse cooling and use most of the pieces but you will have to figure out a way to have an optical sensor for the PCM to read
Re: Possible to use conventional 400 block and build a 377ci LT1?
You could do it but it won't be very easy. There is a way to use a distributor for the signaling but I don't know the specifics. There are a couple guys doing it on the board. The cooling part I have no idea on that one but it could be done. Later Clint
Re: Possible to use conventional 400 block and build a 377ci LT1?
Motor mounts are different. Distributor drive is different (though better). Water pump is different, even where it bolts up. Heads are different.
Re: Possible to use conventional 400 block and build a 377ci LT1?
By definition.... if it isn't built with an LT1 block, it can't be an LT1. 
It is possible to put a Gen 1 SBC in a 93-97 chassis, but there are some difficulties, as mentioned above (plus a few more).

It is possible to put a Gen 1 SBC in a 93-97 chassis, but there are some difficulties, as mentioned above (plus a few more).
Re: Possible to use conventional 400 block and build a 377ci LT1?
I know some guys want to use a GM BowTie block with LT1 heads.
They say the LT1 has a really thin casting in between the cylinders front to rear, especially the 2 center cylinders. They want to use the bowtie block so they can squeeze out enough power to hopefully compete with the LS1's!
There are 2 water holes in the LT1 heads`that need to be welded.
They say the LT1 has a really thin casting in between the cylinders front to rear, especially the 2 center cylinders. They want to use the bowtie block so they can squeeze out enough power to hopefully compete with the LS1's!
There are 2 water holes in the LT1 heads`that need to be welded.
Re: Possible to use conventional 400 block and build a 377ci LT1?
Originally Posted by Mike Comp T/A #57
I know some guys want to use a GM BowTie block with LT1 heads.
They say the LT1 has a really thin casting in between the cylinders front to rear, especially the 2 center cylinders. They want to use the bowtie block so they can squeeze out enough power to hopefully compete with the LS1's!
There are 2 water holes in the LT1 heads`that need to be welded.
They say the LT1 has a really thin casting in between the cylinders front to rear, especially the 2 center cylinders. They want to use the bowtie block so they can squeeze out enough power to hopefully compete with the LS1's!
There are 2 water holes in the LT1 heads`that need to be welded.
Re: Possible to use conventional 400 block and build a 377ci LT1?
Originally Posted by 1racerdude
If he is using LT1 heads he won't make enough HP to need a bowtie block.
Re: Possible to use conventional 400 block and build a 377ci LT1?
Originally Posted by Mike Comp T/A #57
I know of several LT1's that are making some serious HP. You can make more horsepower with thicker cylinder walls. That's why engine builders use utrasonic gauges. Block filler helps also.
It has nothing to do with wall thickness or the bore. It's all about putting air in with more fuel to make HP and the stock head castings won't get it done.
LT1 is OK to .030 bore.
Last edited by 1racerdude; Aug 8, 2006 at 09:53 AM.
Re: Possible to use conventional 400 block and build a 377ci LT1?
Originally Posted by engineermike
.060" over and 22 psi boost. . . no problems . . . yet.
With a LT1 block ya are lucky or went through a truck load before ya found one that would do it.
Re: Possible to use conventional 400 block and build a 377ci LT1?
Originally Posted by 1racerdude
It has nothing to do with wall thickness or the bore.
Re: Possible to use conventional 400 block and build a 377ci LT1?
Doesn't matter about the thrust side ya just don't want to run less than .200 anywhere.
If ya got .200 on the thrust side and .100 on the rest it will crack where it's the thinest below .200.
I have run .180 but wasn't comfortable with it.
If ya got .200 on the thrust side and .100 on the rest it will crack where it's the thinest below .200.
I have run .180 but wasn't comfortable with it.
Re: Possible to use conventional 400 block and build a 377ci LT1?
Originally Posted by 1racerdude
It has nothing to do with wall thickness or the bore.
In theory, the cylinders should be perfectly round. The thicker the wall thickness the better chance that it will stay round and have a good ring seal. This is were you pick up the horsepower. That's why engine builders use torque plates and block filler. The also check several blocks with the ultasonic gauge before they pick one to use. You can machine 2 different blocks exactly the same and one will make more horsepower than the other on the dyno.
Re: Possible to use conventional 400 block and build a 377ci LT1?
Originally Posted by Mike Comp T/A #57
You can machine 2 different blocks exactly the same and one will make more horsepower than the other on the dyno.
Mike
Last edited by engineermike; Aug 8, 2006 at 01:29 PM.


