'77 cutlass supreme 350 to 455 swap.

[Guest]

hi again, my last post is to keep my car running til this swap <img src="/ubbthreads/images/icons/tongue.gif" alt="" />

i have a 1977 cutlass supreme with a 350 and a th-350 trans, colum shift, 4bbl rochester M4MC i believe. i WAS going to put a built chevy 350 in but many factors deterred me. now i have decided to build a mild olds 455 and put it in. i have no idea about olds motors, i need help to know what year will fit in my car, maybe all? i have no idea. what are the best stock heads for this application? i eventually want to get edelbrock aluminum heads but not now <img src="/ubbthreads/images/icons/tongue.gif" alt="" />.

i would like to get above 400hp and above 500 ft/lbs of torque. i need a general layout from someone who knows on what to get/buy/get done to/for my motor. i have not bought a 455 yet. i need suggestions on: cam, stock head code, intake, headers, rockers, lifters, pistons, carb, keep crank/get new crank, keep rods/get new rods.

this car MUST run on pump gas. although im pretty sure 400hp/500ftlb is not a difficult task on a 455 LOL.

this car would be for street use only. i may take it to the strip a few times just to see but thats it. i really just wanna burn my friends who drive rice burners, and ford 5.0s. i hope someone can help me please!

p.s. i have a disassembled chevy 350 2-bolt in my garage. Casting# 3970010

it of course needs rebuilt, i dropped one of the pistons and it's cracked. if anyone wants to buy it, please reply or email me at: guileparasite@hotmail.com

THANKS!

[rocketraider]

500 ft lbs of torque is the norm for a 455. And all in by 2800-3000 RPM.

To give you an idea of 455 capability- 1968-70 the 2-barrel single exhaust cars were rated at over 300 hp. The 1968-70 Toronado W engines were rated at 400, and they were by no means the hottest ones the factory made. 370 hp out of a W30- yah right. The base Toro 455 was 375, as was the Starfire 425 1965-67.

So you see you can build a very mild 455 and still have a stomper in the right car. A 77 Cutlass is heavy but 455 was available thru 1976 so it will be a near drop-in. Use 73-76 Cutlass 455 motor mounts. 455 may stress a Turbo 350 a little. Either build it to take the punishment or get a Turbo 400. All the 350 accessory brackets will bolt on.

Any 1968-76 455 block will do what you ask. Look for an F or Fa cast into the block between the intake and water pump. Best heads are the factory C castings but there are big-valve and small-valve versions. B & E are also a good choice. D, F, H and K are great but cost prohibitive and in my judgment suitable only for a 1000-point show car. A are 425 heads and have to be modified in the pushrod area to work on a 455. J are common as dirt but not suitable for all-out performance. Worked, they're fine for a street engine. 10 to 1 aftermarket pistons combined with C heads usually yield a true compression ratio of about 9.25 which wil tolerate pump gas easily. Be warned that overbored 455s tend to run a little hot so make sure cooling system is up to the task.

Cam is a personal choice. There are several good grinds for BB Olds out there. You want something with a powerband about 2500-6500 to take advantage of the engine's low speed torque capacity and keep the redline sensible. Olds do not like to rev much over 6000. You can use stock rods and crank up to that point, but you should restrict oil to the top end of the engine for such use. Kits are available. You can use stock valvetrain or get an adjustable one.

Not a large intake selection. Edelbrock offers Performer and RPM, and Offenhauser has a couple including a dual-quad. You can always use an old Torker or O4B if you can find one. Holley or worked QuadraJet for carburetion, around 750-850 cfm. A 650 may work better in a heavy Cutlass.

Use 1-5/8 headers for street, 1-7/8 for drag racing thru 2-1/2 or 3 inch pipes and Flowmasters. DynoMax also work good on an Olds.

Enuff to get ya started? <img src="/ubbthreads/images/icons/cool.gif" alt="" />

[Guest]

alright, thanks for that info. i'm going to do some research now. is there any way i could find a block that i would not have to get machine work done on? i need a 455 in near northern illinois if anyone knows of any!

[Don B.]

I did it with a 79 LeSabre. The 455 has a different trans bolt pattern. At least the '70 motor I used did. You may need to install an electric fan for radiator

clearence. I was able to use the stock 'Y' pipe and connect to the cars exhuast.

[Guest]

sooo...what did you do about the different trans pattern? do they make an adapter like they make for chevy motor + BOP trans?

[rocketraider]

All 1965-up BOP-Caddy trans bolt patterns are the same. Pontiac was using it earlier than that. Did that LeSabre have a Chevy engine in it?

Sometime in the late 70s, Turbo 350s started using a universal bolt pattern that fit both Chevy and BOP-Cad engines.