LSX blocks

[gene simmons]

It has been said that the limiting factor for make N/A Hp with a pontiac is the bore spacing.
Why would gm limit its capability with an aftermarket block, and help from warren johnson,to have a block with a 4.25 max bore? i will take a BBC anyday, better block, wider bore spacing, no exotic parts and parts availability.
Does anyone consider the LSX block a chevrolet? i can't make the connection, there are no parts from a small block or big block that will interchange. i would say no,but, gmpp has a bowtie cast in the side of the block, and there are even valve covers that say chevrolet.

[disc0monkey]

your about to start a **** storm. do a search there are dozens of pages on this debate

[Mr. P-Body]

Gene,

The bore spacing doesn't limit power output, per se. It DOES limit cubic inch potential, which in turn, CAN limit power. At the 500 CID range, there's no big advantage to the BBC with the 4.250" bore. It still needs a 4.25" stroke to get it there. Now, a 4.500" bore with the 4" stroke is a different matter. That's how "502" gets there. But a 505 Pontiac (IA-II based, 4.25" stroke) will make more torque than a 502 at the same level of tune. The 502 will certainly make more high-end horsepower, if the Pontiac is somewhat conventional in nature.

But comparing the Chevy to the Pontiac is apples-to-donuts. One is a great low-end/mid-range power plant (street applications is where it really shines). The other is a great high-revving power plant. And applying all the "goodies" available for the BBC today, is not a fair comparison, either, as there was a 20 year interruption in the developement of the Pontiac. Stick around a couple more years, to see what Tiger heads will do for the Pontiac. None are out there in max-developed form yet, unlike Big Chief. Forget the old rectangular port heads. Pontiacs have moved beyond that level of power, even with just Edelbrocks.

NOTE: Our shop doesn't care what color you paint an engine, we'll build it. We have mass experience with both BBC and Pontiac.

LSx engines do use at least two part numbers from the old small block Chevy. The lifter (factory hydraulic roller) and rod bearing. There are other engines from GM Powertrain Div. that use those same parts, though. That said, there is no design relationship between the old small block and LSx. LSx is actually much more like a Ford than it is like a Chevy. And the heads? Artwork, man! All in all, LSx is a great design, especially in the "modern world" of OHC and multi-valve heads. GM's "in your face" pushrod engine! Of course, this is just my opinion... I could be wrong!

Jim

[David Holmberg]

And they (GM and the racers) found out the problems with 4 head bolts per Cyl, just like we did. The only thing they could do is add another bolt location. With the new head coming out for Pontiacs, needing a new (ford) intake, why not make a block with 5 bolts for us too?

Most will never need it, but those that do REALLY need it. If you think Pontiacs are really getting faster now, just think what would happen if there wasn't any head gasket issues...

JMHO.

BTW, I race and hang out with a LOT of LSx guys and they ALL love the new block! None of them are bitching about needing new heads, or what the block costs.

[Mr. P-Body]

David,

While at Norwalk in '05, there was an '05 GTO with "the world's fastest LS1" (their words). It went 7.19 @ 198! Twin-turbo/alcohol... It had LS2 heads. Pretty awesome car!

We learned, as did Ford, to use larger than original head bolts (302 vs. 351W). The modifications to LSx are tricky, as there's not a whole lot of room to work. Bigger bolts/studs can make the addition of bolts unnecessary, depending on how much boost is being applied.

Jim

[big_gto]

GM must think we all have extremely short memories. October 2007 issue (pg 84) of HPP has an article on GMPP's LSX engine block. The Chevrolet bowtie is embossed on the lower edge of the block. In time the truth always comes out. The GMPP LS series of engines is a GEN III chevy small block! But, we all knew that already. It may be a great engine, but not a Pontiac, for better or worse.
If GM were like Ford & Chrysler back in the 1950's & 1960's we'd all grown up driving GTO's with 350 chevy engines. That's just wrong. Swap a 540 IA II engine in a `69 Camaro Z/28 to really boil the blood of a chevy guy!

[goquick]

Or a 460 Ford in to that 69 rs camero like I did !!!:D

As long as it has a bowtie cast on the block, I want nothing to do with it for my own cars. And gm wonders why after they p'ed on us in the late 70's why we are frankly not interested in thier new cars with g whatever names instead of names people actuly know and can remember.

[MetalHead175]

I'm thinking a 426 style hemi would be pretty sweet in a first gen camaro :) only problem is fitting it in there
-Jason

[goquick]

Hemi is ok, but it has respect from all car lovers. So it is not near as cool to see a chevy guy cry when they see a Ford engine (any size:D ) under the hood of their favorite love 69 camaro's hood. Oh, the hemi fits in the first gen camaro too. Headers make Pontiac headers look extremely falling off a log easy though.

The best one I've seen is a built slant 6 mopar under the hood (an early ss/rs type at that!) of a 67 camaro. The guy got tired of rebuilding 327's. :p :D