[mhgamber]

Hey guys, there is a scrapyard here in mississippi that has a 69 grand prix J model, body is pretty good but interior looks like it has been open to the elements for 25 years. the owner said that this car had a 428, and wants $600 for the whole car. I dont need it but is a 428 a good engine to pull and use? is it worth anything? will the heads fit my 66 389 block in my 65 GTO conv? he also has a pretty smashed 67 lemans, very rough but looks like good taillights, trunk lid, a few odds and ends. anyone interested in this stuff? email me at [email protected] if you want more info.

[mhgamber]

Hey guys, there is a scrapyard here in mississippi that has a 69 grand prix J model, body is pretty good but interior looks like it has been open to the elements for 25 years. the owner said that this car had a 428, and wants $600 for the whole car. I dont need it but is a 428 a good engine to pull and use? is it worth anything? will the heads fit my 66 389 block in my 65 GTO conv? he also has a pretty smashed 67 lemans, very rough but looks like good taillights, trunk lid, a few odds and ends. anyone interested in this stuff? email me at [email protected] if you want more info.

[Old Man Taylor]

If I remember correctly the "J" model had a 400 and the "SJ" model had a 428. Make sure you get the code number off of the block.

http://www.jimspontiac.homestead.com/Index.html

[Will]

428s are great engines, and a complete, rebuildable one is easily worth the $600. If it's an SJ and that's the original engine in it, chances are it's a 4-bolt main. It should have #62 heads. Rated 390 horsepower stock, the highest horsepower rating of any stock Pontiac engine. Rebuild it to stock specs and put it in your car in place of the 389 and you'll be very pleased. Or, port the heads, beef up the rods with some ARP bolts (or new forged rods) and put a nice cam in it and go have some real fun.

With a 4" stroke the 428 will rev more easily than a 455 and with the extra cubes it makes more torque than the 400 and smaller engines.


----------------------------
'72 Formula 400 Lucerne Blue, Blue Deluxe interior - My first car!
'73 Firebird 400/4-speed Black on Black, mix & match.

[pvan]

My 69 bonne 428ho came with long branch exhaust so I was wondering if he could get a visual confirmation of it being the 390hp version if it also had factory long branch exhaust?
Mine has 16's but they are the same specs as 62's. Will's explanation of a 428ho is right on, get a nice cam, arp's for the rods, keep the 10.75 to 1 compression, balance it, get a street port, and you got a real mail hauler in any model of Pontiac.
I'm not a drag racer but I am installing a 200hp shot of two nitrogen and one oxygen for rare occasions when I need to turn my heavyweight into a light weight.

[Lloyd-TX]

was a 350 horse 400 4V, but it COULD have been equipped with a 428, 370 or 390 horsepower. Both were optional on the J model, while the 370 horse 428 was standard on the SJ.

You would need to check the block and cylinder head casting numbers and date codes to properly identify the engine and see if it is original.

If my memory is correct, the 390 horse 428HO had the "068" camshaft and the long-branch streamlined exhaust manifolds.

Way back in the early 70's, a good friend had a super-loaded '69 SJ 428HO. Bright yellow with a black cordova top and black leather. TH400, A/C, 3.23 posi, etc. SOB could absolutley smoke my 350HP '69 GTO without breaking a sweat! For such a land barge, those cars MOVED! Of course, one could still buy 100 octane leaded premium back then - for 36 cents/gallon!

He bought that car used, then bought a NICE split-bumper '72 Camaro SS 350. His younger brother had a gold '70 1/2 Z-28 and a loaded Buccaneer Red '74 T/A 455.

Brings back lots of good memories!

Later,
"455HO" Lloyd

1972 Formula 455HO; Lucerne Blue; 12.96 @ 104 MPH @ the '03 PSN's; 12.50's or bust this year!
1970 GTO 455HO; Palomino Copper
1972 GTO 455HO; Sundance Orange

[pvan]

Hey Lloyd, nice story on the SJ its seldom that folks mention that big and heavy don't always mean slow.

I did get whooped hard by a buddy with a nasty 4speed 69RoadRunner with slicks on juice last summer... but I have more then once whooped up on some hot muscle cars that mistakenly first thought my 428HO powered 3.23posi barge was a sled.

They discovered this barge/sled has wings!

[HotRod2go]

I remember my SJ and it was FINE and FAST! I did read somewhere that the "SJ" emblems were messed up, (vendor issue), in '69 so the factory had more "SJ" cars than emblems so they put the "J" ones on several cars. Maybe someone else could confirm this.

[android 211]

In regards to the 428 in the GP what it came with all depends: Auto and a/c cars all had the 067 camshaft while 4 speed cars had the 068 (HO) cam.
ALL of them came with standard log exhaust manifolds. The long branch style won't fit. You could put on ram air manifolds if you wanted an improvement. 4 speed cars would have 48 heads like a GTO, automatic cars had 62s. Check your service manual. Its all there.

[69GPModJ]

I've got a '69 Model J that came with a 370 HP 428. They're good engines. If it's a 428 in a '69 GP, it's got four bolt mains.

The "standard" engine for Model Js were 400s but you could get a 428 in a Model J.

69GPModJ

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