I'm restoring a 79 Trans Am with an Olds 403. The engine was pulled by the previous owner in '85 and I got the engine in a bunch of boxes. However some of the boxes have apparently vanished since '85. Are bolts for all the small blocks mostly the same? I don't have a single bolt for the engine asides from the bolts for the carb.

I'm having problems finding local sources for 403s as its a bit of an oddball engine since it was only offered for a few years and I was wondering if it might be easier to hunt down a different Olds small block

 

Any SBO will have the same bolts as a 403 EXCEPT the head bolts. You'll need head bolts from a 77-up motor, since Olds changed from 7/16" to 1/2" on the later motors.

 

"I'm having problems finding local sources for 403s as its a bit of an oddball engine since it was only offered for a few years and I was wondering if it might be easier to hunt down a different Olds small block"

That is a pretty heavy car, the the extra cubes and torque are nice to have. A 455 is taller, so the other choice would be a 350. No real sense in losing the extra 50+ cubes, and you already have it! What issues are you finding as regards to parts? What is your over-all goal for the car?

 

I think his question was that he wanted to know if another SBO (like a 350) would be an acceptable source for all the bolts and small parts missing from his 403 basket case. For that matter, you could probably get a 260 for free and use all the bolts from that.

 

Well I'm going for collectors plates so everything has to be original or at least appear to be. I'm going to beef up the drivetrain abit. If I do find another SBO to take all the bolts from, do you guys know if ARP or some other supplier carries head bolts for the 403?

What other Olds small blocks were made after '77 other than the 403 that I might be able to find head bolts from?

While I'm on the topic I got a couple more questions that hopefully you guys can help me with. The car came with a holley 600cfm universal carb which apparently needs an adaptor plate for it to mount properly to the 403 intake. Does anyone make a good carb for the 403 that will bolt directly to the 403? I don't know if I'll be able to use the Holley and the adapter because its 3/4" tall and that might give me clearance issues with the shaker hood.

The car also came with some really nice chrome long tube headers, Doug Throrley I think. They've been sittin in the attic for a while. Are the exhaust ports on the 403 heads the same as on other SBO heads? I won't be able to use them on my Trans Am because of going for collector plates and big chrome pipes would be an automatic rejection. However, I've always had a thing for late 60s/early 70s 442s and Cutlass's and I'd love to get one sometime down the road. I'm wondering if it would be worth keeping the headers in the hopes that I get one of these some day or if I should just sell them and put the money towards my Trans Am.

 

Yep

260, 307, and 350s were all available at various times after 1976. I was serious about the 260 in my last post. It's a pretty worthless motor and you can often get one for free.

Just get a Qjet and be done with it.

All Olds motors have the same exhaust port spacing. The difference between SBO and BBO is the deck height. As a result, it usually isn't possible to use small block headers on a big block and vice versa. The headers usually run into the crossmember, motor mounts, starter, oil filter adapter, etc, when used in the wrong application.

 

Sorry about that, thought he was talking about startingg over with another engine.


"Just get a Qjet and be done with it."

Excellent advice!! It's OE, works great, and the linkage will be correct. Some say that the late 70s Q-jets are the best ones.

 

Another question on compatibility. The previous owner had gotten all the pulleys and accessory brackets chromed. Again, can't use chrome for collectors plates so I'm going to be selling them on Ebay, or possibly on here if anyones interested. Do all/most Olds engines use the same accessory brackets and pulleys? I just want to make sure my posting for these things is correct when I go to sell them.

Thanks

 

Your problem is that the 403 T/A uses brackets unique to that car. The normal (and common) Olds brackets do not work on a T/A. I don't know what pulleys were used on the T/A.