Recently purchased a 403 with a TH400. my car is a 67 olds with the 330 and 3 speed tranny. Im looking to purchase all new parts top to bottom an build the 403. I was told the 330 heads will bolt on and 330 crank will fit in. is there any major work i have to do? or can
essentially just clean everything up and put it together.

 

Best heads to use with stock pistons are the 5, 6, or 7's from a 350.

And unless you're looking at big power the 330 crank would be unneccessary.

 

yeah im not looking at anything wild just something i can drive often but also get good power from and enjoy.maybe burn some rubber here and there. i dont have 350 heads would the 330 heads be worth doing inhave them theyre off of my running car and are free

 

If you do change heads, I'd upgrade to at least 2.000/1.625 valves, and possibly even the 2.072 intakes while you're at it. That valve size worked on the 400 BBO.

 

do i have to drill or machine to change the valves? or do they just swap in?

 

The valve seats need to be cut for the larger diameter valves. Your machine shop will do this as part of a valve job.

 

Actually the 1967 330 heads are the only factory 64 cc head so with stock 403 pistons they are a better choice if max compression is your objective. The #4 head is also the only 330 head from a 39 deg bank angle engine.

 

I wouldn't get too worked up about the size of the chambers. All pre-1973 SBO heads have about the same chamber size as cast. The published numbers are typically NHRA blueprint specs and require some machining to achieve anyway. As-cast chambers vary and are usually a few CCs above the published blueprint numbers. Valve jobs, changing valve sizes, and milling will all change chamber size. This is why you should CC the heads.

 

The #4 heads will be fine, as long as you are happy with the compression ratio that results, which affects cam choice, and fuel requirements. Have bigger valves fitted per above. A head rebuild can get very very pricey so maybe ask what a fully done set of heads costs at your machine shop, with new larger valves, new guides, hard exhaust seats, refacing. You may at that point be near the price of a set of AL aftermarket heads.

As for the crank, if you have a 330 and are parting it, sure, use it in the 403. Use the 403's beastier "XC" rods. You will have the assembly balanced either way so why not use the best available part- the forged 330 crank. Don't lose its flexplate that is required with it. Use any harmonic balancer you have in good condition. Beware the new wobbly China ones.

Oh, and don't forget this: [I can offer you a discount at 99% off if you order today!]

http://www.ebay.com/itm/150646769737...84.m1555.l2649

 

And I'll add that those Play-D'OH main studs are more rare than SMW 403s!

 

Chris, you've got to much free time on your hands. Ken

 

what ive done now is kept the 330 crank and block aside and im having the 403 crank polished amd cylinders honed with new bearings rings an piston so stock but fresh as the engine was in great shape internally.i have mild intake and 650 carb hedders but i now
wouldnt mind putting a cam but from what im reading i cant go any bigger than stock unless i change out my entire valve train any ideas??!

 

I hope im not annoying anyone too much yet lol but I got new updates. So I really sank my teeth into the car this weekend and I called my engine shop to hold off on doing anything until Monday or tues. when peeling everything apart from my car I discovered my block and crank is a 1967 330ci and it has the 1972 7A heads on it. I would like a mild street/strip build is it worth my time to bore the 403 block .20 use the 330 crank, 403 rods, flat tops and 7a head with the holly intake? of is there going to be a ton of math and complexity to building that safely. aswell ive heard a lot of commotion about how olds cant go any bigger than a stock cam without doing a head job??

 

Not true. There are lots of cams you can use with the stock stuff. I offer a few myself.
It's always a good idea to replace the springs though, no matter what.
Based on your final compression ratio I'm sure we can come up with something that'll work just fine.

 

what size cam brand etc would you recommend