Motor Opinions...

[Kato Asmodeus]

Hello, Everyone...
My Question For Today Is, What Does Everyone Think Is The Best Choice Of Engine To Put Into My '86 GP?...
I Was Stuck Between 3 Choices: 1- Rebuild And Keep My Original 305, 2- Drop In A Simple 350 Or 3- A Nice, Beefy 455...
What Are Your Opinions On This And If You Have A Different Idea, I'm Definitely Open To Suggestions...
Thanks For Taking The Time To Read This Forum Post...

 

[84/ttop]

Can't go wrong with the awesome torque of a 455. There is no replacement for displacement.

 

[GhettoRacingKid]

What are you looking to do and get out of the car?

 

[Blake B]

^^ good question... Or find a 400 and have the best of both worlds.

Let us know what you want out of the car

 

[565bbchevy]

305 waste of time and money, 350 sbc everyone has done that, 455 now were are talking and 400 works well too.

 

[83gbody]

I'll say 455 I won't one of those myself

 

[dogsht]

Well the sbc 350 is without a doubt here especially since you already have a sbc under the bonnet the cheapest easiest route to go. But then you don't have anything particularly fun or cool. And isn't that the point of having & building up an 86 Pontiac Grand Prix instead of finding a cheap old fwd 4 cylinder for the cheapest basic transportation? Every car show cruise in is flooded with them like looking for belly buttons under a shirt.

Begin with the end in mind then factor in achievable practical reality. You know using a factory original numbers matching 70 Cuda 426 Hemi might sound cool but.. where as a Pontiac 455 even 400 stroker hell even a crazy 500 Cadillac might be realistically & financially achievable.

 

[Bonnewagon]

I'd say Pontiac 400. That's a LOT of motor for these cars. 455's are getting scarce and expen$ive but 400's are still pretty available for cheap. And while a 455 has gobs of stump pulling torque which is not really needed on our cars, even a Pontiac 350 is a nice upgrade. But a 400 is just right.

 

[454muscle]

455, hands down. Why?

1. More reliable than the 305, especially the 350 and 400.
2. Gobs of tire-shredding torque, sure to make jaws drop to bystanders and also passengers.
3. And I can't say why, but your gas mileage will be better with the 455 than the 350. Only reason I know this is because I went from a stock 350, to a mildly built 350, and then to a BBC 454. My gas mileage was better than ever and the torque was unreal. In your case, BBO 455 -- should be similar.
4. If you do a nice exhaust setup, the 455 displacement produces a nice deep powerful tone, whether you go with an H or X pipe and either Flowmasters or Magnaflows or what have you. When I had my H-pipe and 2 Flowmaster Deltaflow 40s the sound was deeper than anything I ever heard -- with stock exhaust manifolds! When I drove away from the exhaust shop every single person around me, both driving and pedestrians were staring at what that sound was.... it was awesome.

 

[-83MONTESS-]

1. More reliable than the 305, especially the 350 and 400.

I was agreeing on everything you said except this. How does one figure an engine's reliability?