265 cid lt1.

[justanova]

does anyone know the major differences between the 265(4.3L) lt1 that was installed in some 94-96 B-bodies and the normal lt1 other than displacement? Are the heads/intake/ injectors/throttlebody/block etc... the same? The reason I ask is I might have an opportunity to pick one up cheap, and I want to do an lt1 conversion to my 70 impala. and if all else is the same I could always change out the shortblock.

any help is appreciated, thanks.

Brett

[442olds]

The heads are different, Cast Iron (265) vs aluminum (Z or Vette), I think the intakes are the same, as well as the throttle body. Everything else should be the same.

[justanova]

thats what I was thinking,

I am aware of the iron heads, but are they diff. than the iron heads on the 5.7L lt1 in the impala SS? Like smaller runners?

[Texas Hotrod]

Car Craft had some really good articles on LS1s in their last 2 issues.
It seems not only bore/stroke measurements are different, but valve placement and valve sizes are smaller on the small cubed engines.
The aluminum heads all share the same casting configuration, but the machining processes are different. The small engines have smaller valves that are spaced closer together, to fit the small bore. The 5.3 has small valves w/a wider spacing (I think). Intakes can be swapped, the truck design makes for better hp#s at higher rpms.
The iron heads should be the same casting, harder to upgrade and less desireable. As for the ports, I am not sure and you can run higher compression w/aluminum heads.
Car Craft took a 5.3, installed better pistons, had bigger valves installed, ran a bigger cam, and used a stock truck intake and made over 600hp at the crank. The valve pocket castings are really thin, so excessive porting is not possible but they can be modified.
The Corvette heads seem to be the best ones to run. The castings are better and the machining process were updated.
The Denali engines would be the hot ticket. What would be better than all aluminum and pushing 6litres?

I have a 5.3 that I intended to use in one of my projects. I have too many engines to choose from and side-lined the LS1.
As long as I don't change my mind, it is for sale if you know of anyone interested. It is a steel block/aluminum heads w/o intake w/exhaust manifolds.

TEX

[justanova]

thats some good info TEX but I think you may have misread my post I was inquiring about the 265cube(4.3L) LT1 that was used in some 94 thru 96 caprices. I remember reading somewhere that the bore/stroke dimensions mimicked the original 265 but they have a rod that is 5.9 or so inches long and you can put the 265 lt1 crank into the 5.7l lt1 block and use off the shelf 5.7l lt1 pistons for a 302 cid lt1.

so on the 265lt1's are the heads and intake diff that the 5.7 iron headed lt1's?

Thanks for the info though the ls1's are extremely bad ass and I can't wait to get the one going in my nova.

[Texas Hotrod]

You did say LT1, but I had LS1 on the brain. Sorry for all that misinformation.
LT1s are good engines, the only bad thing is that nothing else will interchange. LT1 parts will only fit LT1s.
The really weak link in the LT1 is the Opti-spark distributor. I searched for a good used one a while back and couldn't find one anywhere.
Edelbrock makes an intake so a carb can be used w/an HEI distributor. Sure has a cleaner look to it than the mess of having a wiring harness.

[Q ship]

The really weak link in the LT1 is the Opti-spark distributor. I searched for a good used one a while back and couldn't find one anywhere.

There are alternatives, search google, impalassforum, or camaroz28 forum for "ltcc" or "delteq". They still use the opti for a trigger, but the high voltage side is all seperate.
Justanova, you could probably find some of the answers to your questions on the impss forum, I think it has been discussed there.

[justanova]

Justanova, you could probably find some of the answers to your questions on the impss forum, I think it has been discussed there.

thanks, I dont know why I didn't think of that