big inch pontiac lsx...
big inch pontiac lsx... anyone out there make old popular pontiac engine sizes for our lsx cars? as in like a 389, 400, 421, 428, 455.... ive heard of a 421 stroker, but havent seen much popularity with it due to the piston design to get the cubes. i think its 4.030x4.125. i know we have 383's, 402's, 408's, 427's, 454's. but i dont want to put one in and play it off for a different motor. i guess i think it would be cool to have a 400 trans am or a 428 or something.
anyone else have these thoughts at all? or is anyone saying their 427 is a 428?
guess im seeing most shortblocks in popular chevy engine sizes and no pontiacs. would this be a little bit of different machining and some custom pistons to make up one cubic inch difference?
anyone else have these thoughts at all? or is anyone saying their 427 is a 428?
guess im seeing most shortblocks in popular chevy engine sizes and no pontiacs. would this be a little bit of different machining and some custom pistons to make up one cubic inch difference?
A lot of rebuilt LS7's are actually 428's when a 4.130" bore is used.
I think MTI (from Houston) did a 455 GTO a while back, but they went out of business a long time ago. You can still find some of the old MTI guys around different Houston shops, like LME or HKE.
I think MTI (from Houston) did a 455 GTO a while back, but they went out of business a long time ago. You can still find some of the old MTI guys around different Houston shops, like LME or HKE.
12 Second Club
Joined: Feb 2006
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From: Catlettsburg, Ky
i've always thought the idea of bringing back the poncho heritage in to a late model LSx motor was pretty cool.
now, if only i could find a 3x2 manifold for an lsx motor, I'd go on and build a 389. lol
now, if only i could find a 3x2 manifold for an lsx motor, I'd go on and build a 389. lol
but it sucks cause we already have to murder the cowl for 1-4bbl....lol
yeah, im going to check into these things. i just think that nostalgic cubic inch would be cool.
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TECH Enthusiast
Joined: Nov 2005
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You ever looked at the old Poncho motors? All are big blocks, you aren't going to get it into a F-body with out some cutting of the sheet metal in the engine bay. The only modern car it could work with would be the GTO because of the extra space around the bay.
You could probably physically get the engine in there, but the second you wanted to do exhaust you would realize you had real problems.
You could probably physically get the engine in there, but the second you wanted to do exhaust you would realize you had real problems.
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I think he is just talking about building a LS series block to the CI of an old school Pontiac, like the GTO 455. It would be neat to say, build a trans am with a 6.6 LS in it, maybe add a raptor hood and some 6.6 decals to the hood.
It's just for aesthetic/conversation sake.
It's just for aesthetic/conversation sake.
I think he is just talking about building a LS series block to the CI of an old school Pontiac, like the GTO 455. It would be neat to say, build a trans am with a 6.6 LS in it, maybe add a raptor hood and some 6.6 decals to the hood.
It's just for aesthetic/conversation sake.
It's just for aesthetic/conversation sake.
on the other hand, bringing up the 6.6, i think a 402 qualify's for a 6.6, so i might rock that idea....
Joined: Nov 2003
Posts: 6,216
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From: Wichita KS / Rancho San Diego
Pontiac 428 was actually a 427 - 4.125 x 4.00 - same as an LS7, IIRC.
370 was the Pontiac engine size for 1958 ... that's a popular aftermarket LS1 build. I don't think the are any Pontiac 370 emblems you could put on your car. Like you say, 402 = 6.6 and that's a good match.
370 was the Pontiac engine size for 1958 ... that's a popular aftermarket LS1 build. I don't think the are any Pontiac 370 emblems you could put on your car. Like you say, 402 = 6.6 and that's a good match.
the biggest thing to get a similar feel is to get the bore and stroke close and get a cam thats gonna idle close to a factory raIV cam (big cam wiiiide lsa like 117). leave it fuel injected and it'll be sick
