Anyone run a 403?

[alphamale]

I am considering running an Olds 403 in my 85 cutlass. I have heard all the negatives associated with them (low HP, webbed mains, etc. ) However, I want to put an olds motor in and I have read that you can make these low reving torque monsters. Would purchasing a remanufactured motor as a base be a better idea then a junk yard find? Or would finding a cheap, running 403 be better to start with and clean up? I like the idea of an olds powerhouse in my daily driver. I don't plan to beat it up at the strip or wind it higher than highway speed. But I would like to break the tires loose once in a while and have something under the hood that most don't. Any suggestions or advice would be greatly appreciated. Thanks.

-Bud

 

[pencero]

Don't buy a remanufactured engine man. I bought one once and it was trash. Sold the car asap. Didn't really realize it was trash til one of my friends pulled up in the same model car and I took his for a spin and wondered why his car was much more responsive and smoother than mine. If you buy a re mfr 350 that's kind of a different story because the 350 is the engine they used to teach people with to start; but if you buy a re mfr anything else its easy to get stuck with somebody else's foolish mistakes and they might not show up until just after the warranty expires too - or if you change anything to gain hp and there's a mistake somewhere else on the motor (which you probably will right who wouldn't) you already violated the warranty in most cases so now your stuck w broke motor cant get $ back. Better idea is to look at a good engine builder's shop and see whats happening. You'd be surprised how many people build engines and then never come back to pick them up or finish paying them off and they're sitting there 100% finished but the guy quits racing or sells his project. At least with an engine like that you know who actually built it and their reputation but if you don't you can just look it up or make some calls and ask around.

 

[alphamale]

Thanks for the input, much appreciated. I was kind of thinking the same thing, although I hadn't thought to call around and see if people left their projects behind (great idea by the way). I think I will start looking for a good runner and go from there. Right now I have a buick 350 which runs strong, I just want some Olds power under the hood eventually.

 

[FE3X CLONE]

I've had a 403 in my '81 for years. It's a fine engine that will hold up just fine. I rev it to 5500-6000rpm when "racing" or having fun and it doesn't have any thing special done to the bottom end other than ARP main and rod bolts. Stock reconditioned rods and crank with cast replacement pistons. You can find better pistons now days for the 403 which will bump the compression when using the stock 4A heads.

In my case I used the stock replacement pistons (.030 over) and installed a set of 7a 350 heads to up the compression. The 7a heads are a little better flowing head as well.

With a 221/227 camshaft, 9.4:1 compression, Edelbrock performer RPM intake, 750cfm Speed Demon carb, headers and a 3000 stall converter it's managed a best of 13.1@103 mph on drag radials out of the box. Never really tuned the thing other than adjusting the timing and changing a couple of jets. I know it has more in it but just never messed with it.

All that being said, I'm still a bigger fan of a 425/455 BBO swap. Not really much more work and loads more torque. 🙂

 

[alphamale]

Do you happen to know the weight difference between the 403 SBO and the 400-455 BBO? I prefered to stay small block just for the weight reduction off the front end and I didn't plan on taking it to the track or anything. If I could get a 455 for cheap though I probably would go that route though.

 

[olds307 and 403]

If the numbers are right 530 for a 403 and 620 for a 455, supposedly. Honestly a junk yard 403 with mild cam would do what you want. My 8 to 1, Performer cam added 403 with a 2004R, 2400 stall and 3.42's would do 1/2 throttle burn outs and felt fast. Never ran what I wanted or should have ran at the track, low 15's. Just add KB pistons, will give 9.5 to 1, better cam, lifters, springs and will easily do what you want.

 

[1SlowBu]

Nope

 

[olds307 and 403]

:?

 

[wonderboy24]

i am running a 403.keeping it olds

 

[JayPat83]

Thanks for the input, much appreciated. I was kind of thinking the same thing, although I hadn't thought to call around and see if people left their projects behind (great idea by the way). I think I will start looking for a good runner and go from there. Right now I have a buick 350 which runs strong, I just want some Olds power under the hood eventually.

I saw a 403 yesterday at my parts guys place near knoxville tn. Be interested in that?