Ok, now that I'm in the right topic section, I have a few questions.Where do you drill the 7a 350 heads for the extra water passages? I laid the gaskets for the 403 on the 7a heads and I can't see anything different about the passages, am I missing something? Also, I can't find true torque spec. for the head bolts, my chilton book has as far back as 1982, 307 and 350 these are the same 1/2 " bolts, it says 125 ft lbs and 130 ft lbs, but another spec. from the internet somewhere I find 95 ft lbs, any help would be appreciated.
403 olds questions
- Thread starter 87oldssalon302sbc
- Start date
- Status
So, don't worry with the steam holes and my Chilton book is correct with 130 ft lbs, thanks for the support. Next question, my combo is, 87 salon, 403 with stock rebuilt shortblock, 7a 350 heads with 403 valves,flowtec headers, preformer rpm intake and cam kit, 670 street advenger, pro-comp hei stock type dist., rebuilt turbo 400 with b&m components, 3400 stall converter, 7.5 rear with 373 gear and posi., 28x10.50 et streets. Would I benefit with 411 gear as I have on hand another whole rear complete out of the car waiting to be installed? My car is mosty for bothering the neibhors and being hauled to the dragstrip when I have the time and can afford it. This hasn't been ran yet to see how the 373 will do, but I was thinking while the car was down for the engine swap I could do the rear too, I have a 323 and 342 also to choose from. Which gear would be better higher or lower?
87oldssalon302sbc, sounds like a good set-up.
Did you mill the heads at all? Yea torque the 403 heads to 130-ft. lbs. Even try a 750 carb! 4.11 would be quicker around town, and better for the track, but the rpm difference is only 270-300rpm's. At 60mph you'll be at 2686rpm w/3.73's, 2952rpm w/4.11's.
Did you dyno the engine yet?
Did you mill the heads at all? Yea torque the 403 heads to 130-ft. lbs. Even try a 750 carb! 4.11 would be quicker around town, and better for the track, but the rpm difference is only 270-300rpm's. At 60mph you'll be at 2686rpm w/3.73's, 2952rpm w/4.11's.
Did you dyno the engine yet?
If its for the drag strip, I'd go with 4.11's. They are "lower" gears. However, I would almost be cautious when putting such low gears in a stock 7.5" rear due to them perhaps overloading the rear. Although, they aren't a huge step up from 3.73's which came stock.
I like your setup but I still cannot understand why you Olds guys put Olds motors back in. It doesn't seem like the economical route let alone the performance one. Maybe I just can't appreciate brand loyalty being that my car came with the right one already.
I like your setup but I still cannot understand why you Olds guys put Olds motors back in. It doesn't seem like the economical route let alone the performance one. Maybe I just can't appreciate brand loyalty being that my car came with the right one already.
The heads haven't been milled, just surfaced to clean up, no port work either just the bowl for the 403 valves. The first motor I put in the car was a 383 sbc, then I came across all the stuff to build a one piece rear seal 302 sbc, it loved wot. I owned the car for four years and when I pulled the 307 out I started looking for 403 parts, in the midst of all this I've also aquired two complete 455 engines. But I don't like the way the 455 fits these cars the 403 is a much better fit and all the accesories bolt right on from the 307. There is no possible way to do any of this economicaly its just an expensive toy, I doubt the 403 will be the last engine in the car but we will see,I also have a 9 inch for the rear as time and money premits.
drogg1 said:
Chevys arn't always the cheapest to build, if you look carefully. I picked up a very low milage 1970 455 with big valve E heads for $900, with all other performance upgrades/overhaul parts/machine work I'm only spending about another $1500. I should have roughly 440hp and 560ft/lbs torque when I'm done, all for $2400. Plus the way I'm building it, it should spin 6000 RPM, no problem. Also got a BOP TH400, all heavy-duty internals and shift kit for $350. You just have to know where to look.
Not to mention it's a direct bolt in, no messing with motor mounts, electrical wiring, battery placement, etc.
I only say cheaper because I could build a forged internals 355 or 383 stroker sbc. for 1800 MAX that makes around 425/425. Only, reason why argued. I actually like the BB olds/buick/pontiac idea. Just I could never see justifying outting a SBO in and trying to make it run like a chevy. That is a good deal on that transmission however. I wish I could find a cheap way to rebuild my th350 with hardened internals and a shift kit for 350 bucks.
drogg1 said:
Who cares? Who are you to tell someone they should have got a Chevy engine when they asked nothing about opinions on the engine choice?
Maybe his sbc's were blue smoke puffing cam burning turds like most of the 70's to 80's, I have seen. The SBO makes a very nice flat torque curve. The modern aftermarket heads/blocks is what puts Olds at a disadvantage. Factory vs factory, the Olds stuff was better made.
- Status
Similar threads
