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Shake66

428 engine

Question

I have a 1971 Pontiac Lemans Sport with a 428 engine in it. How rare are these engines and are they reliable? I am thinking about pulling that engine out and putting in a LS3 pontiac engine in my Lemans Sport. Good idea or not?


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there will a few pop in here and post. i think new modern engine will be fun but, i know will agree with this, if it is the original matching numbers engine, that you should still have it in your possession for jus in case.


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keep it clean it up make a nice table out of the block then when needed reassemble


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The LS3 will be more reliable, better gas mileage, etc... as it is a newer engine. Depends on what you want to build, if you're after restoring the car to it's natural beauty then the 428 is what you should rebuild and go with. If you just want a nice cruiser or track car, go with an LS motor.



I have an LS3 variant in my Camaro and it is a fabulous engine, I love it BUT if you want to build that Pontiac glory, the 428 will be best option :)


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:lol2: Been waitin for Frosty to chip in on this one. Knew the 428 was a 60's engine and never offered in the car. Badge on the rocker was a dead give away too. As Frosty stated, New tech in an old car can/will produce some major headaches to install. If its running driving combo, I'd lean towards keeping the set up. A bolt on injection unit (direct replacement for carb) would help with gas milage and response. A nice exhaust system and your golden. The 428 produces gobbs of torque and is as reliable as any other Pontiac motor. Will also save you time N cash you can put towards cosmetic upgrades that's needed. Good luck with whatever set up you go with. :dancingpontiac:


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:lol2: Been waitin for Frosty to chip in on this one. Knew the 428 was a 60's engine and never offered in the car. Badge on the rocker was a dead give away too. As Frosty stated, New tech in an old car can/will produce some major headaches to install. If its running driving combo, I'd lean towards keeping the set up. A bolt on injection unit (direct replacement for carb) would help with gas milage and response. A nice exhaust system and your golden. The 428 produces gobbs of torque and is as reliable as any other Pontiac motor. Will also save you time N cash you can put towards cosmetic upgrades that's needed. Good luck with whatever set up you go with. :dancingpontiac:

Take it from JUSTA, he knows from experience what he is talking about.. He has a 428 with tri-power in his GTO. Its not original to his GTO either but it is a screamer when it is tuned and running right. The point is the 428 is a great motor. I would be reluctant to toss it unless it was totally trashed.

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Take it from JUSTA, he knows from experience what he is talking about.. He has a 428 with tri-power in his GTO. Its not original to his GTO either but it is a screamer when it is tuned and running right. The point is the 428 is a great motor. I would be reluctant to toss it unless it was totally trashed.

Sorry bro....I have the 421. :lol2: I don't believe the 428 was offered in tri-power. "If I remember correctly" The 428 was the 1st shot at a bigger bore motor than the 421. 2nd shot = 455....Gotta remember Pontiac, Chevy, Ford, Chrysler SPONSERED drag racing back then. Win on Sunday....Sell out the lot on Monday!! 428's are fairly rare. Limited run, same as 421. Short of the block being cracked or all ready bored out to its limits. It's a treasure to somebody. It was unreal to find my 421 tri... 66 was the last year that the Pontiac 421 was offered in packages. (including my GTO) Next up 428. I was looking for a 389 4bbl that maybe I could build into tri. That's what my car had from the factory. :indian: When I got it, it had a (spit :drool: ) but Bad a$$ 396 Chevy. So 421 seemed like the perfect fit for me. :dancingpontiac:

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OK JUSTA, I stand corrected. You have a 421. So now you made me pull out my copy of "Pontiac Musclecar Performance 1955-1979 GTO/Firebird/Super Duty/Ram Air" by Pete McCarthy.



I was wrong on the years the 428 was produced, it was produced in the late '60s, 1967 to 1969 to be exact. The 428, like the 421, is desirable because they come stock with 4-bolt mains. The 389, and many 400s and 455s did not. Some 400s and 455s are 4-main engines, depends on the year and vehicle it was going into - so you have to pay attention to the casting number on the block to determine the 2 vs 4-bolt 400s and 455s. JUSTA was correct, tri-power was not an option for the 428, nor was there an H.O. option.



However, there were 428s built with the H.O. exhaust manifold (but it is not considered an H.O. engine). These engines went into the high performance Grand Prixes or the Catalina Enforcer police cars. Pontiac is not as well known for its police cars, back in the day, as compared to Chevy, Ford, and Dodge, still it was a solid performing car for heavy duty police, fire, and ambulance work.



Still, the 428 is not original to Shake66's '71 Lemans Sport Coupe. Still, I think it is a solid motor and well worth keeping if it is good condition.


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OK JUSTA, I stand corrected. You have a 421. So now you made me pull out my copy of "Pontiac Musclecar Performance 1955-1979 GTO/Firebird/Super Duty/Ram Air" by Pete McCarthy.

I was wrong on the years the 428 was produced, it was produced in the late '60s, 1967 to 1969 to be exact. The 428, like the 421, is desirable because they come stock with 4-bolt mains. The 389, and many 400s and 455s did not. Some 400s and 455s are 4-main engines, depends on the year and vehicle it was going into - so you have to pay attention to the casting number on the block to determine the 2 vs 4-bolt 400s and 455s. JUSTA was correct, tri-power was not an option for the 428, nor was there an H.O. option.

However, there were 428s built with the H.O. exhaust manifold (but it is not considered an H.O. engine). These engines went into the high performance Grand Prixes or the Catalina Enforcer police cars. Pontiac is not as well known for its police cars, back in the day, as compared to Chevy, Ford, and Dodge, still it was a solid performing car for heavy duty police, fire, and ambulance work.

Still, the 428 is not original to Shake66's '71 Lemans Sport Coupe. Still, I think it is a solid motor and well worth keeping if it is good condition.

The 428 block was built to BECOME a stroker for racing. BUT, Did not come off the production line as such. Modify as desired, then have fun! :dancingpontiac:

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there you go Shake66, straight from our experts. what is your plan now, with the added info?


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