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Topic Review (Newest First)
07-17-2006 01:35 PM
Mustangsaly don't understmate the 403 this one is makin big HP 403 Olds 9.70 compression 491 hp 489 tq

9.70:1 compression
7a heads ported for low lift flow by FCR
custom hydraulic flat tappet cam by FCR
street dominator intake modified and ported by FCR
800 holley dp
hedman g body headers 1 3/4 (JUNK)with 18"extension
cast replacement pistons ( this engine was the one Bandit bought from Dave H and was already overhauled and balanced)
ARP rodbolts, headbolts and main studs
Cryoe'd block and crank

_________________ 1 877-215-1800 TOLL FREE
OLDSMOBILE PERFORMANCE PARTS AND ENGINES. Kooks headers Ultra Dyne cams and performance parts for Olds. Cometic gaskets Still $150.00 a pair.

lots of Olds motor & tranny info here

Olds 403 has No steam holes !

a stock 403 has potential, it has a bigger bore than a BBC . a good set of early 350 olds heads is the way to go (350 olds heads need the head bolt holes enlarged to 1/2" ). The 403 responds well to a bit more camshaft and compression. use earlier 350 heads ('68-'72 will do it, but the '72's are the best) to raise the compression, and an Edelbrock Performer-grind cam (these cams are available from other sources than Edelbrock, who I suspect purchases them from another supplier).

A stock 403 Olds engine has tons of torque. Carbs aren't the problem. The problem is the heads. Their combustion chambers are too large, around 83ccs. This results in a compression ratio around 8.0 to 1. Try to find a set of 350 heads from 1973 or before. This will raise compression enough to even think about HP.

If you add 72 or earlier 350 cylinder heads, your compression will be abound 9.5:1-10:1. It will increase your HP considerably, though you'll probably want to add a cam that can take advantage of that high compression.

small block olds head info here some good Build up info here.

a Good site for 403 Olds and all Olds info there a guy on the ROP Olds site in Omaha Ne. goes by Mr. Olds that will talk to you on the phone (super nice guy) and knows his Olds and the 403. Terry FCR PERFORMANCE .com 1 877-215-1800 TOLL FREE
OLDSMOBILE PERFORMANCE PARTS AND ENGINES. We sell Kooks headers Ultra Dyne cams and most other performance parts for Olds.
07-17-2006 10:46 AM
MAUSS I've got a '79 TA with the 403 also... I'm pretty sure that it's the short tailshaft TH350. I used to remember stuff like that, but you know what they say... the memory is the second thing to go (I don't remember what the first is).

There's a pic of mine on my web site. car pics
07-17-2006 10:22 AM
larryblack The chevy transmissions have a different bolt pattern from the engine to transmission. This includes manual trannies.

The Buicks, Oldsmobiles and Pontiacs have the same engine to transmission bolt pattern. Hence the reference to BOP.

You can use a chevy tranny wit the 403 olds engine in your pontiac, BUT you must use an adaptor plate as was previously mentioned.

BTW, TH350's came in 6", 9" and 12" tail shaft arangements. Hence the reference to short, medium and long tailshafts.
07-17-2006 09:07 AM
camaroking383 that is good info the only other question i have is can i bolt a chevy th350 to this motor or if it has to be olds tranny what cars (make model) can i rob one from. I appreciate the info. i dont even really know if there is a olds th 350 or if yall are talking about chevy th350
07-14-2006 08:32 PM
el pollo All 48,000 or so 403 equipped Trans Ams had the TH350 behind them. You can bolt a BOP 400 to them, but if you have a stock 403, it's not worth it. The 400 consumes more horsepower to turn than the lighter 350.
07-14-2006 12:05 PM
meev182 i think they came with a bop th400, not a 350, but i could be wrong. a bop trans and a chevy trans can go together with the use of an adapter plate, jegs and summit sells them for like 50 bucks.
07-14-2006 11:55 AM
camaroking383 but i guess that would olds th350 and chevy th350 wont bolt up right
07-13-2006 10:29 PM
el pollo TH350.

Never heard of a short tail or long tail 350 though. Could that be a BOP versus a Chevy??
07-13-2006 02:19 PM
nitro_baller4692 i think it was a 350 short tail shaft.not possitive though
07-12-2006 07:59 AM
79 trans am

what type transmission came factory behind a 403 olds in these trans ams

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