L98boy

Hello,

I have a question. In 1970 the LT1 engine option was a 350, came with a aluminum block, and aluminum heads right? If this is true why did GM go back to using cast iron blocks and heads in their 350 Corvette engines? It does not make any sense. Isn’t that going kind of backwards? Thank you for your time.

Shaun

standup

.......don't think they came with alloy blocks/heads.......my understanding is the extra 70HP was made from 11:1 compression, solid lifter cam, maybe some fancy work to the heads.......I'm pretty sure everything was cast iron, which would explain why they didn't continue it.........

FinnShark

At least the LT1 block was iron, but I'm not sure about the heads, my guess would be iron... But wasn't L-88 heads aluminium? And ZL-1 was all aluminium? I think that the main clue in here is the cost... At that time it was much more expensive to do those things from aluminium than from iron.

duntovlives

as finnshark stated, im sure cost is a huge factor. no doubt that the 90 lbs (or so) in weight is an advantage. but i read tons about debates on the alum vs iron conflict. seems that some feel that the iron deals with the heat issue better.

in 70 LS5 was the bad boy option. 390hp. but prior to 70, when u could get an L-88 i think it was all iron. the L71 had 5 more hp and u could get it with aluminum head=L-89

i have also read that GM had trouble with porosity in the alum casting process

im going from memory here, which is cloudy at best on a good day :confused: - so, pls no one cuss me if i am way off base. but, i would really like to hear what others have to say on the alum vs iron issue :cheers: :confused:

Gordonm

No LT1 motors were aluminum heads or block. They were iron. The intake was alum. but that was it. I don't recall any small block leaving the factory with alum block or heads until the 86 vette had alum. heads.

L98boy

Thanks for the information guys. I really appreciate it!

Shaun

Robert N

Correct. Irn block and heads, aluminum intake.

stpman

:iagree:

A friend of my has the LT1 in a '73 Camaro Z28, iron block and heads

Steve :steering:

jrzvette

in 70 LS5 was the bad boy option. 390hp. but prior to 70, when u could get an L-88 i think it was all iron. the L71 had 5 more hp and u could get it with aluminum head=L-89

The L-88 and L-71 were both offered in 1967-1969. The L-89 was an aluminum head option for the L-71 only. The L-71 with either iron or aluminum heads was rated at 435 hp while the L-88 was quoted at 430. But it is generally acknowledged that the L-88 put out more like 550 to 600 hp. The lowere hp quote was an attempt to keep it out of the hands of the general public as it was a race engine, and GM figured that most hp junkies would opt for the higher rated L-71.

Bob K

There was a all alum (block and heads) option avail in the early 70's. I beleive it was the ZL2 option.

Just like the L88 it was not meant for everyone. That's why the factory rated the L88's at 430 hp and the Big block with solid lifter and tripower at 435 hp. I drove a "REAL" L88 in 1973 (while I was working at Reedman's). It was the fastest car I have ever driven. Quite a bit faster that the 435 hp cars.

Bob K.

P.S. In the early 70's the Used car lot at Reedman's was neat because all the muscle cars were being traded in all the time. Only the Vette's and Jag's were kept locked.

Gordonm

The only factory all aluminum was the 69 ZL1 motor. Only 2 were factory installed. The L88 was an aluminum head iron block 12.5 to 1 high lift solid cam monster. There was an L89 which was a 435 horse motor with aluminum heads. The L88 with headers dynoed around 560 to 580 HP. With a little tweaking they easily went over 600 HP. The early 70s motor was the ZR2 which was a racing package in 71. Only 12 produced. Aluminum heads and iron block but it was a 454 solid cam with 425 HP. Had all the ZR1 components but instead of the 350 LT1 it had a 454 high performance. The Ls6 could be had without the ZR2 package and I think about 188 of these were made.


[Modified by Gordonm, 3:10 PM 9/12/2003]


[Modified by Gordonm, 3:23 PM 9/12/2003]

A C

:iagree: Right on. No all aluminum small blocks were put into Corvettes until the LT1.