Top End Kit for my Olds 350 in my 1987 Cutlass.
- Thread starter spencer83
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I saw that post earlier. I'm always on CL. What I meant was...455 is a good option I should think about huh? Especially since my engine isn't worth squat.
The big number by the #1 or #8 spark should help tell what year it is.
That 403 with early 330/350 heads with 2.07"/1.625" valves, drilled for 1/2" head bolts, opening bowls, clean up porting, would be a drop in and go make the 400 HP, depending on the Erson cam, I know a dealer and 400+ torque you want and ALL your accessories will bolt right on. Do a compression test on it, that should tell you a lot. A bearing check, pulling a cap, maybe a rod and a main is a good idea before it goes in. The factory 4A 403 heads have huge chambers, mine were 86 cc and have a horrible exhaust port and tiny valve. Your car have A/C, correct? That will not bolt on that 455 without custom modifications. The 455 with make 450 HP and 500+ torque but will need high compression pistons and attention to detail on the bottom end. Any 72 and up for most part would have the dreaded J head, similar exhaust port to the 4A with a bigger valve, they need hours of grinding. I would run the clearances on the high end of factory spec, many more bottom end issues due to a very heavy, crank, rods and pistons.
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I would stay away from the big block myself, but you can go that route. They are wider, need expensive headers, and accessories don't always bolt up, but they make more power easier. On the same, the 403 wouldn't be a bad option either (its my engine of choice), but you can expect to sink some cash in it.
My 403 build is right around that 400hp mark you are looking for, and I have about $4-4500 into it. The biggest thing was finding good deals on parts. Going with big block heads on a small block will probably help get your power where you want inexpensively, but you will need flat top pistons and some milling on the heads to get decent compression.
Do note, the bigger the engine gets, the more mild it will be at a given power level (generally). I wanted to stroke a 403, but decided against it for cost and because I got a cheap deal on a bottom end that worked. But even a stock 403 is 53 more cubes than a 350, and still fits right in place of the 307 coming out.
My 403 build is right around that 400hp mark you are looking for, and I have about $4-4500 into it. The biggest thing was finding good deals on parts. Going with big block heads on a small block will probably help get your power where you want inexpensively, but you will need flat top pistons and some milling on the heads to get decent compression.
Do note, the bigger the engine gets, the more mild it will be at a given power level (generally). I wanted to stroke a 403, but decided against it for cost and because I got a cheap deal on a bottom end that worked. But even a stock 403 is 53 more cubes than a 350, and still fits right in place of the 307 coming out.
A lot of talk about girdles. That's a dangerous subject. But I will say that a halo girdle does nothing but keep your block in less broken pieces, in my opinion. Race engines have proven that a solid motor mount stretches the walls of your block when the engine torques, and causes main failure. And a halo girdle does nothing to stop THIS failure. To me it's just fancy straps with the aid in cap walk. Most experienced olds guys run rubber or no engine mounts with front and mid plate with full pan rail girdle. Even seen solid motor mounts with full rail girdle, and lots of HP. Halo girdle helps cap walk. Full rail girdle also keeps mains safe. So girdle selection is build specific. So 400hp don't mean get a girdle. Cap walk is high RPM related most the times I've seen. So ask your engine builder or machine shop. Any style girdle isn't cheap and require machine work.
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