what is the ls-7 (tri-power 454?)and was it ever produced?
how much do u have to bore to get a sleeve to fit ?
is there a sleeve that keeps a 4.030 bore on a 350 block?
what cars were the 400sbc originally installed on?
Thanks a lot! :cheers:

 

anyone :confused:

 

Well, if nobody's gonna answer I'll give my best shot...

The LS7 would have been the follow-up to the L71 in 1970.
I think you are correct that it was going to be a tripower.
I'd say for sure they made a few but they never sold any.
I've read articles that talked about magazine writers getting
a shot at one. I think it was the one they described as being
like as powerfull as a jet taking off.

I don't remember how thick a sleeve is. .083 comes to mind,
but I'm not sure. I don't have anything handy that says, so
I can't look it up. Seems like I remember there are two normal
thickness sleeves. I think they're a slight interference fit - maybe
.001 - and they use some type of glue to hold them in place.

Yes, it's normal to sleeve a block to whatever size the rest of the
cylinders are. So if your 350 needed a .030 bore but one of the
cylinders was messed up you'd sleeve that one and bore them
all 30 over.

The 400 was generally put in heavy stuff. I think they were all
2 barrels, so you're talking low-end torque to move weight.

 

400s were used in full size chevy cars from 70 - 76 and in chevy trucks from 70 - 80.

 

Early 70s chevelles had an option for a 400 sbc. Talk about full size cars :D I hope nobody from chevelles.com is lurking around.

Rob



[Modified by robzr, 11:27 PM 5/5/2002]

 

I think the LS-7 was the 454 version of the L-88. I do not think it would have had the tri-carb set up. It may have been sold over the counter as a crate engine but you will have to confirm with some of the old timers on the board. I am not sure what the stock compression was.

Chevy advertised it but never offered it as a regular production option. I once saw an old Vette ad for it for sale on Ebay.

Can't help you on the other stuff. Got some sleeve questionsof my own for another project coming up.

 

thanks :cheers:

 

Yep, I was wrong. The correct follow-up to the L71 was
to be the LJ-2 460HP tri-power.

Man, they really dissed the Vette big-blocks in 1970.
Chevelles got the good engine????

 

At one point or another, the 1970 Corvette was scheduled to receive five different big block engines... In the end, only the LS-5 made the option list.

LT-2 was the first to get the axe. It would have been a 454 cid version of the ZL-1 from the previous year. I have seen very little information about this engine asit was dropped before the engineering drawings were done for the 1970 AIM.

The LJ-1 and LJ-2 were 454 cid versions of L-68 and L-71 from 1969. Basically 454 tripower engines... One with oval port heads/hydraulic cam the other was a rectangular port heads/solid cam engine. They made the the AIM, but were cancelled well before 1970 production started.

The LS-7 made it closest to production... The AIM shows a May 1970 cancellation date so it's pretty obvious that the engineers were still doing their best to get it into production before it was finally killed. If the information presented by GM to the AMA (as well as parts listed in the AIM) is to be believed, the intended production LS-7 would have been nothing more than the Chevelle LS-6 engine with the exception of closed chamber aluminum heads and solid lifter cam with slightly more lift (and a lot more duration) than the "143" street solid lifter cam used in many of Chevrolet's high performance engines of the 1960s/1970s.

Chevrolet later released an engine assembly (available from the parts counter) called LS-7, but it had little in common with the original LS-7 concept intended to be a Corvette RPO and was in fact more of spinoff of the L-88.

Regards,