Choice of 403 or 455 in my Cutlass

[hankthecrank]

OK, I wasn't expecting such a resounding vote for the 455, I thought the 403 would get at least some props. Right now, I want the 307 gone and put something in place so that I can drive my car daily. I'm gonna swap in a running 403/TH350 from a trans am that I just found, do it on the REAL cheap. Meanwhile, I will keep looking for a 455. My biggest issues with the 455 are the exhaust manifold/headers, and the fact that I don't want a smog version of the engine. I am really trying to find a 68 to 72 version, which will have most all the parts I want to start with.

Thanks for the replies to everyone, I can't wait to get this thing on the road again and start cruising Oldsmobile style!!!

 

[dogsht]

Assuming you have the 200-4R get that either built to match your 455 power or if you are going to run a fairly stock 455 with regular radial tires you can probably get by with just a good shift kit like the one www.ckperformance.com sells and maybe adding a inexpensive trans cooler. If you put some good gears like 3.42/3.73 in her you will want all the benefits that the overdrive trans provides.

 

[G-Body_Vet]

OK, I wasn't expecting such a resounding vote for the 455, I thought the 403 would get at least some props.

I'm a fan of cubes too but a 403 beats the hell out of a 307 any day. If you're trying to stay cheap for now the 403 is the way to go since it's a drop in deal. I acquired an '85 Cutlass back in the day with a 403. The rings were so bad that it literally blew a little oil out of the driver's side exhaust, yet it would still light up that one-legger rear end with 2 series gears until I let off it.

With a decent 200-4R and a 3.73 rear-end you'd be in business.

 

[Peter]

an olds 350 with good heads aint too bad either :lol:

 

[hankthecrank]

OK, so here's the dilema, the whole reason I posted this in the first place. I have available for purchase a 1979 403/TH350 complete minus carb for $500. I also have available a 1976 455/TH400 long tail complete for $650. The 455 is not my first choice in parts combinations, I'd rather have a 68-72 version. Now I have seen some 68-72 455 engines in various states of . . um . . . shall we say disrepair, but I really like the idea of putting something in over the winter and having it driveable for next summer. Am I just being a whiny b*tch cause I have so many great options or what? Someone slap me and set me straight, please.

 

[88hurstolds]

403's suck unless you build them and if you're gonna put the money into a motor might as well go with a 455, they drop right in.
403's came with the same amount of HP from the factory as a VIN9 307 did just had more torque.

 

[nicknewbie]

I am almost done with my 1976 455. I got mine out of a old motor home, took a lot of work it was so rusted that you could not read the numbers behind the water pump the carb was corroded shut full of algae water thankfully it saved everything under it. worth it for a motor with 50k for 200$ and 150$ worth of scrap 😀

 

[all4gss]

I'll chime in for the 403...

1. direct bolt in for the 307, no one will know the difference except that "403" cast near the motor mount and who's going to get under the car to look?
2. Stock 403 came with 185hp & 320ft/lbs which is laughable until you realize it did it with 8:1 compression and the torque comes in at 2,200 RPM!!! Compared to the 307 vin Y with 140 hp & 255ft/lbs.
3. the stock bottom end is only good up to 5,500rpm but I rarely get higher than that on a street car.
4. the 403 responds very well to a compression ratio. Look for '72 rocket heads to boost CR.
5. later you can add cam/intake/carb/etc...

If it were me I'd get the 403 and use the $150 you saved on the 455 and the $580 bucks you won't have to spend on those 455 gbody headers and get a set 68-72 Olds 350 heads (72 are best due to hardened valve seats).

My first build was a 84 calais with a stock 403 from a vista cruiser. I added an edelbrock performer cam/carb/intake and even with 8:1 CR it was a blast to drive for a high school kid. I always wanted to add those '72 heads to wake up the horsepower but the torque was more than enough to roast the tires through the 2.41 gears.

Here's more details if you haven't read it yet:
http://www.442.com/oldsfaq/ofe403.htm


I'm a 403 fan

 

[mechanic58]

Just a simple observation....I do believe the 403 Olds is the same engine family as the 307 that's already in the car. It should be a fairly straight-forward swap. The 455 however is a 'big block' olds motor and is different. Might be easier to slide the 403 in there. Just my $.02.

edit: Guess I shoulda read the last guy's post before I made mine....lmao!

 

[oldiejams]

i would go with a 455, just because saying 455 sounds badass!