Is it worth it to keep my 350 Rocket, or....

[Blake442]

My 455 is an absolute blast to drive.

The Olds 455 is a great choice... *ss loads of torque with even the mildest of builds. You could spend around $4000 and have a motor that'll rip your c*ck off when you stab the gas! Or go relatively mild, and still be well over 500 ft/lbs. with rock solid reliablity, and great street manners.

Just think, if the most potent factory 455 was rated at 390 hp and 510 ft/lb stock, then with a little extra you've got one killer receipe for a fun motor.

All you need to do is help an Olds motor breathe better, and the power they make is unreal.

Whatever way you go, staying with an Olds motor will be a lot less work than swapping to a Chevy.

 

[85 Cutlass Brougham]

Well, it all depends on the level of power you want. The mid 70's Olds 350 is no "Rocket" in stock form and would require a lot of parts to make it really fast. It is also a heavier engine than the Chevy, if that matters to you. Unlike many, I have no issue with using the most cost-effective engine you can find. I have a Chevy in mine and 99% of the world could care less. And even if they do care, I don't. Either engine would be best served with a non-stock set of cylinder heads as neither came with anything to write home about in stock form. Even the vaunted Vortec L35 heads are really just marginal in a serious performance application for the Chevy. The 455 is an interesting choice, but it does make an already nose heavy car even worse. It's fine for a drag car, but if handling matters to you it's not the best choice.

Depending on the power level you want then, the Chevy may or may not be the cheapest. The big question in determining this is how much more will the accessories, transmission, etc. run you to put a Chevy in there vs the Olds vs the cost offset of the cheaper parts of the Chevy vs the price of building the Olds. You also have to realize that the rest of the car needs to be upgraded if you plan on a significant infusion of power, or you'll just start throwing parts everywhere. Remember that G body's chassis and drivetrain was never intended to take much power, when it was designed the top engine maybe had 150hp. You will need to upgrade the transmission with any of these choices if it is stock, and the rear axle just goes without saying. The driveshaft becomes an area of concern too if you run slicks and serious power. It is on the small side stock and will be a fail point too with anything too serious. I figure that 350-400hp is the ragged edge of reliability with the stock powertrain in a G body on street tires with a 7.5 axle. Anything more will break stuff on a consistent basis.

Anyhow, what IS the intended use of the car, and what kind of power do you want? Your answer to that question will determine the most cost-effective way to proceed with your car.

 

[midwestls]

My guess would be that the intended use of the car will be fun right??? If so let me mention that currently I have a 69 350hp 350LT1 out of a Vette in my LS. It's alot more fun to drive then the 4.3 it replaced. But I ride in my buddys 88 SS with a 454 and I end up hatin my car all over again everytime. Big blocks are fun. Period. Thats why I'm swapping to a big block this summer. I don't think I've even got 200 miles on my 350 yet. But like 85 Cutlass said, most G Body drivelines are not very strong. Plan on a rearend, transmission and driveshaft to go with it just for starters. But I too agree there is absolutely no substitute for cubic inch's.

 

[joe_padavano]

The Olds 350 is a very underrated engine. It has a better bore/stroke ratio than a 350 Chevy and with a little porting to the heads it will make quite a bit of power. Your first problem is your smogger 76 motor. As noted above, get Number 5, 6, 7, or 7a heads from the late 60s-early 70s motors (note: do not confuse the 1972 7a heads with the 85-90 7A heads, which suck). Get a Performer RPM, decent headers (even the new aftermarket SBO exhaust manifolds don't flow much better than stock), and a good dual pattern cam.

 

[v8power]

My guess would be that the intended use of the car will be fun right??? If so let me mention that currently I have a 69 350hp 350LT1 out of a Vette in my LS. It's alot more fun to drive then the 4.3 it replaced. But I ride in my buddys 88 SS with a 454 and I end up hatin my car all over again everytime. Big blocks are fun. Period. Thats why I'm swapping to a big block this summer. I don't think I've even got 200 miles on my 350 yet. But like 85 Cutlass said, most G Body drivelines are not very strong. Plan on a rearend, transmission and driveshaft to go with it just for starters. But I too agree there is absolutely no substitute for cubic inch's.

BIG BLOCK CHEVY, you will never go back. but as stated before, you will need a rear end and a transmission, but worth it 8)

 

[85 Cutlass Brougham]

Well, my point is that if you want a balanced car, go with the lightest small block you can that makes the power you want. I would hate my car with a big block because I love corners more than straight line acceleration. My car was built as a balance between acceleration, fuel economy, handling and occupant comfort. I essentially tried to make it stock feeling, but better everywhere.

 

[midwestls]

This is tru, a big block will weigh your front end down some. But it's the twist that I love.

 

[custom442]

I just don't understand the whole big block phenomena. A few of my friends have them, one is in a chevy truck so this one doesn't count - it always gets beaten because he hasn't modified the suspension...go figure :? .

The fastest car I've ever been in was a chevelle with a 400 sb and it destroyed any engine run against it at the drag. I can honestly say there is no car that would touch it unless it ran against a pro street or bracketed out. It was so consistent and didn't overheat even after doubling up, it ran between 10.0-10.25 all day long.

Also with today's aluminum heads for small blocks (especially chevy) it's almost a no-brainer to build anything but.

 

[85 Cutlass Brougham]

For my money, if a car is not at least running low 11's a big block is a huge waste of gas and weight. It only really makes sense in a restored car, towing rig, or pure drag car. For all the money it costs to run a mild one, you could have better all around performance with an LSX and spend no more money. F bodies with LS1's run 12's with no more than slicks, and they weigh about the same ( better aerodynamics though). I'll also add that unless you run better than the 11's, there is no reason to have a gutted car, Especially when most mild air conditioned F bodies can run the number. The best money is spent with a small block. In fact, the fastest car I ever drove was an 81 Mustang with a 351W in it that ran low 10's.

 

[custom442]

^^^ X2

You're loosing a lot of driveability on the street every second you shave off after a 12 second quarter car.

My ideal street car would be a car that can reach top speed faster than the other car can get to third gear. That would include a SB powerplant with tons of low end, and really aggressive rear gears that would send it to 80mph before you can sneeze.