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Old 05-12-2005, 07:53 PM
firechicken383 firechicken383 is offline
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Oh well if its going to be mostly street in your bonneville, then that 403 could make an excellent choice, just depends on what your after. I've had a few in street cars and they are alright. Alot of T/A's came with them and thats what I'm into so thats where my experience with them is.

When you said you wanted it to run a low 10 or high 9, I was thinking drag strip only. That was 9's in a 1/4 or 1/8 mile? If its a 1/4, you might as well forget it with that 403 and street car. But if you meant 1/8, then you shouldn't have too much promblem running 9's with a 403.

They can be great if your looking for a 400h.p. engine or less. They can definately be made to produce more though, but I wouldn't try to push much over 400-450 h.p. with one due to the main webs. I mean, I dont know exactly what you want from this car, but a 403 can be pretty stout for the street.

Because it is an olds engine, parts availability isn't near what it is for chevy (or price either). But ****uming you don't go with high $ aftermarket heads, you could run the new KB pistons with your current heads or run flattops with a set of earlier 350 heads. ( I would choose the second route if your rebuilding this thing) The earlier 350 olds heads (4,5,6,7,and 7a) flow approximately the same on the intake and about 20 cfm more on the exhaust. (the earlier heads would need a little modification to run on the 403 block, but nothing to bad) As far as cam, listen to tom, a "torquey" cam is what you need. (Somethin less than 220* @.050) A edelbrock performer rpm and any of the small tube hedders should work fine. I like a quadrajet for mild applications of less than 325 h.p. For over 350 I would go with whatever brand you prefer (edelbrock, holley, demon, etc) Everyone will have their opinion on what carb is best. BTW, I listed them in order I would use them.

Also be aware that you will likely have to convert the valvetrain over to an adjustable setup. This stuff will add up quick and you will likely spend plently of hard earned money on it but with the earlier olds heads and around 9.5 compression, and a cam in the 216-222 range, you should around 300-375 REALISTIC horsepower and some pretty good torque to go with it. (In other words if a magazine did an article on the same build, it would make over 400 horsepower) Just add a 2500-3000 stall convertor and 3.42-3.73 gears and you should have a great street runner.

BTW, I agree with tom, I'd try not to bore it more than .020 if possible. I'd also have the block decked too. Add ARP rod bolts to the rods and resize them. If Its like most olds blocks, it'll have very little wear, they seem to wear good IMO.

Good luck with it and ask if you have any more questions.
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