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Olds 403 Buildup

Keep it clean! :)
foxtrot_lima_bravo
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Postby foxtrot_lima_bravo on Sun Jan 04, 2009 11:39 pm

Just finished cleaning up loys of "spy-bots" that were slowing down my computer. What an arduous task…

I actually not sure of the tire size, I'll have to take a look. The rims are the '86 Grand National style and they have 235 tires... The gears do make a huge difference and this can is not a daily driver...

Thanks for the advice on the heads -- I'll have to finish up with the current project first. :-)

TBRtat2
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Postby TBRtat2 on Mon Jan 05, 2009 5:52 am

The biggist weak point i know of is the cooling system, thats where i hear about problems. IMO never bore a 403 more then 40 over, or you will drasticly increase ur chance of over heating.

Mine is running flat top pistons, giving around 10-1 compession, which lets me run any type of gas with no detination. And I have a slightly more agressive "truck" cam then you which is giving me much more tourqe and a bit more hp. (which is perfect for my tall rear gear)

Deffinitly get a dual exhaust with headers, the 403 needs a lot of room to breath, my motor was first in a buick with with the stock exhaust, which it ran good but when it went into my cutlass with headers and duals, it completely change the way it runs, and woke it up.

My 403 now has around 20,000 miles on the rebuild and it runs as good as ever

As for the heads, i kept the stock heads, but the heads and the block where each milled 0.010 (0.020 combined)(BUT doing that much required some creative milling for the intake to seat properly :lol: )
From what we looked at, the 350 heads had to small of chambers for the 403, the pistons are wider then the combustion chambers. Which may increase compression, but it limits the spread of the burn on the pistons.
1987 Cutlass Supreme, with an olds. 403, punched out .040", Deck & heads milled .010" each, Crane fireball cam, edelbrock intake & 750cfm carb, th350 trans, w/ higher stall torgue converter (approx. 1000rpm over stock stall speed). And a 2.14 rear gear. (yes I said 2.14)

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olds307 and 403
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Postby olds307 and 403 on Mon Jan 05, 2009 10:20 am

I have had MANY cooling problems. Killed a very fresh looking bottom end, copper bearings in a short time. I am sure now after adding two different radiators(now a 2 1/4" dual core aluminum), Flowcooler hi flow aluminum water pump, a 160 high flow thermostat, new 16# rad cap and Plymouth breeze dual fans(was a 7 blade clutch fan). Without the fans cutting in, it gets to 210 in -30 temps. The underdrive pulleys have got to go period, before spring.
88 Cutlass Supreme Classic, Mild Olds 350, 2004R, 3.42 open for now....94 chev Z71 4x4, TBI 76 350 Olds, 5A heads,A4,204/214 cam,Sanderson's and duals, rebuilt 4L60E,3.73 gov lock, 2010 Challenger SE, Stone White, leather, 18" wheels, 2000 Dodge Dakota Sport Club Cab 4x4, 3.9 v6 and 3.92 no slip.

TBRtat2
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Postby TBRtat2 on Mon Jan 05, 2009 11:48 am

1 option when having a cooling issue, is to run an engine oil cooler.
1987 Cutlass Supreme, with an olds. 403, punched out .040", Deck & heads milled .010" each, Crane fireball cam, edelbrock intake & 750cfm carb, th350 trans, w/ higher stall torgue converter (approx. 1000rpm over stock stall speed). And a 2.14 rear gear. (yes I said 2.14)

foxtrot_lima_bravo
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Postby foxtrot_lima_bravo on Mon Jan 05, 2009 2:06 pm

I've never run an oil cooler -- how do you plumb that in? Does the oil boss(oil filter manifold) need to be removed? Any part numbers for the kits that were used on your olds motor?

Also, I'm wondering if an aluminum radiator would be a big improvement?

Thanks.

TBRtat2
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Postby TBRtat2 on Mon Jan 05, 2009 3:02 pm

For me, I am running a remote oil filter (i didnt like how close the filter was to the headers) but I havent mounted a oil cooler on mine yet, (it has not needed it yet, but i have only had it in the cold).
But if i did it would be easy, just run in line with the remote oil filter.
There are kits for oil coolers, that mount a adpter between the filter and the mount, but space is the issue with those.

Also check your trans temps, I have heard from a few guys over the years that had heat issues with a 403 but only under heavy loads (towing, etc.), they found out there trans's where running hot, and in turn heated the motor thru direct heat tranfer (trans case to engine block), and by heating the coolant in the radiator (from the trans cooler in the radiator).

As for my radiator, i am running the stock "Heavy duty" aluminum replacment for a a cutlass with a 307 from my local auto parts store. its a 2 row, with decent size rows.
1987 Cutlass Supreme, with an olds. 403, punched out .040", Deck & heads milled .010" each, Crane fireball cam, edelbrock intake & 750cfm carb, th350 trans, w/ higher stall torgue converter (approx. 1000rpm over stock stall speed). And a 2.14 rear gear. (yes I said 2.14)

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olds307 and 403
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Postby olds307 and 403 on Fri Jan 09, 2009 9:01 am

Did they deck the block any after installing the pistons? How much of an overbore? It will make a big difference on actual compression ratio.
88 Cutlass Supreme Classic, Mild Olds 350, 2004R, 3.42 open for now....94 chev Z71 4x4, TBI 76 350 Olds, 5A heads,A4,204/214 cam,Sanderson's and duals, rebuilt 4L60E,3.73 gov lock, 2010 Challenger SE, Stone White, leather, 18" wheels, 2000 Dodge Dakota Sport Club Cab 4x4, 3.9 v6 and 3.92 no slip.

foxtrot_lima_bravo
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Postby foxtrot_lima_bravo on Fri Jan 09, 2009 11:50 pm

I did wind up procuring the #5 heads! I did sort of a swap of the 403 heads ++ $$! The number #5 heads are also ported && polished! I'm hoping that this is worth the $$ because it wasn't cheap! Mum's the word on the $$! As I said before, I'm not bringing this auto to the qtr just want to feel it in the seat of my pants. I think that this will be accomplished now. I'm done spending money. :-)

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beeterolds
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Postby beeterolds on Sat Jan 10, 2009 12:40 am

i had a 403 with #7 heads, i never had any cooling problems, i ran a 7blade clutch fan with a 3 row diesel radiator..no problems to speak of
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1983 Oldsmobile Cutlass Supreme
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