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Old 10-09-2005, 06:57 PM
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403 motor

yall got tricks to juice up my 403 for 68 cutlass and maby where to find some body parts cheap

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Old 10-10-2005, 07:08 PM
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i love 403's. i've been told the 455 big block heads will bolt on the small blocks, so if you can find a set with small enough chamber with bigger valves, that would be the ticket. if not find a set of 68-70 350 rocket heads. good aluminum intake & headers, with a cam & stall, it will surprize you.
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Old 10-10-2005, 07:42 PM
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You want to use the c heads if you are on a budget or you can use the edlebrocks they flow as good as the c heads but not all runners are equall.

If you are going to build it to race or beat on requaly then you will need good rod bolts or eagle aftermarket rods.You will also need the oil restrictors in the mains to keep the oil in the bottom end.I would also use studs in the block or if the budget allows use the straps or gurdel.

The 403 is what they call a window block so the mains are weaker then other blocks.
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Old 10-11-2005, 09:52 AM
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do a search there is some good olds 403 info already here. 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.

forget the 455 head idea unless your pockets are running over with money.

small block olds head info here


http://www.442.com/oldsfaq/ofe403.ht...IDEngineDetail some good Build up info here.

a Good site for 403 Olds and all Olds info http://www.realoldspower.com 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.

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