Ok, another disappointing track run and a 10 psi oil pressure drop has the writing on the wall. I have calculated 9 to 1, depending final specs. I already have light weight forged .040" stroker pistons, rings and Scat 2" journal rods. I will also need a 330 crank from an Olds specialist, Halo with studs, rod and main bearings, head bolts and Cometic or Corteco head gaskets. I will use the #8's for now with slight milling, Performer springs/cheap retainers and maybe a 3 angle valve job. I may also reuse the Performer cam and Cloyes Street roller, if in good shape. What about an oil pump and pan on a 5000 rpm engine? Stock pan/ pump or deep/ high volume? I know the block will need bored .040" over, what clearance with 2618 forged pistons? A clean up mill on the block, new cam bearings and balance will also be done. Is an align hone necessary with studs? I just need to get my ducks in a row. I should have $2500 to throw at it come spring. My main focus is the bottom end. I also have Performer and intakes. I plan on getting the front half of exhaust get redone in 2.5" with cut outs. Stupid exhaust broke again. I don't want to go too radical or trans and rear will go next. Also thinking Griffin dominator radiator, Champion 3 core is too small as is. Please give me your thoughts. I want better than a 9.7 in the 1/8.

 

My 2 cents - I would think down the line a little further regarding CR & heads. Run the #'s & see if you can limit compression w/ iron heads using a near or zero deck clearance & being in the 9-9.5 CR range w/a thick head gskt. Leave yourself an option to add aluminum heads later where you can probably bump the CR to 10-10.5 range. It sounds to me like you are gonna end up still looking for more once you get comfortable w/ even this build & that would be the next logical progression that can easily be done w/ your "base architecture".

Might wanna think about moving into an RPM intake, but that is an easy update later.

Deep pan would be a good idea, pump volume should probably be based on your bearing clearances.

If you are switching over to studs & adding halo the block should be line bored.

 

Yes what he said. If you change to studs and/or a girdle an align hone is in order.
Make sure you clearence the rods correctly, they're offset, stock Olds ones aren't.
Again yes on the RPM, sell all the other ones. Even with bad heads the RPM will do better with 424 c.i.
The pistons should have clearence specs with them, if not I'd say .004-.0045 would be good for that size bore.
More cam etc will also be in order to achieve your goals, or you can just throw a 150 shot of nitrous on it as well.

Keep us posted.

 

Mark, what cam would you recommend with 9 to 1, 424 ci and crappy heads for now? Oldsmobile Dave gave me a good link to an experienced Olds builder in Alberta. I will contact him for prices, expertice and maybe to build me a short block. He is currently doing his own 403 stroker. I just looking for high 8's in the 1/8 for next year, nothing ridiculous. I was leaning towards the RPM intake and will add RPM heads with 1.7 to 1 rockers the year after.

 

A TQ40, 220/228@.050 with .504 lift. You can switch to 1.7 rockers and have .535 lift when you get better heads. This would work well with an RPM and a 750 or better carb.

 

If that is all you want why not do a 362? IMO, the 403 is a flawed platform, it is so hard to get a proper hone and ring seal. The 350 is just a better foundation. These forums are littered with tales of disappointing 403 builds. My very mild 9 to 1 355 ran 9.8x with a 2.03 60' in a heavier car.
Get a 350, bore it to 4.125, use stock stroke or add a bit. Flat tops with zero deck and a little mill on your #8s will yield 9.5, perfect for the street. It will be reliable, strong enough to add spray later if you want without a girdle, won't overheat, fun to drive, and less money to build. You can do the whole short block for $2500 (or less) starting from scratch. The extra cubes are just not worth the problems that come with them, IMHO.

 

I do have a 330 forged crank, balancer and flex plate. Looks ready to go but has already been ground .010" rods and .020" mains. How much needs to be removed off the rod journals to run sbc 400 pistons and rods in a 350? I have 76 Olds 350 in my 4x4. That may be plan B. Maybe rings and crank grind or just shove the 403 as is with 5A heads in the 4x4. The chebby computer was meant to run a 9.4 to 1 350 with a tiny cam. Very lazy timing curve and seems to run a bit rich anyways. That might be another option, more in my budget.

 

I just punched some numbers, the 403 would work very well in the 4x4 with 5A heads. Around 9 to 1, could just throw bearings at it, this winter. I am tired of trying to cool the 403, how much worse would a .040" one be? Maybe see if I can sell the pistons and rods I have, money towards 350 pistons. I would need to do the 403 first, to keep the truck running. There are some nice piston options for the 350 but most go with stock rods. How weak are the rods in a performance application?

 

Bore it to 4.155, stroke it to 3.5 and you'll have 380c.i.
Piston choices are almost endless. Plus even a 76 block is probably stronger than your 403.
Crank grind, pistons and rods will run about $850.00 -$1000.00 typically.

Choices choices.

 

FWIW ...

I've always heard that .030 was @ the max one really wants to go on a 403.

 

SBO crank journal is 2.125, SBC 2.100 and 2.00. So, with no stroke simply cut .025 off. SBO p/h is 1.605 with a 6" rod, SBC has multiple options, but an easy one is 6.2" rod and 1.425 P/h which results in zero deck with no milling. Stroker options are a little trickier, but it is still just basic math. Here are a few,
http://www.realoldspower.com/phpBB2/...hlight=stroker
Result is better rods and pistons for less money. If he is still over there on OP, Jamie did a stroker build, but with higher compression.

 

Probably?? 76 block is no different than all the other 68-76 350 blocks.

 

Thanks, the 350 is very tempting. Nitrous is much more reasonable with the 350 too. I have time to think this over. I will get back when I get it pulled.

 

IMO Why skimp on the retainers? Even a high quality sets cheap insurance for "keeping" a valve in its porper place vs through a piston.

 

True, my point is I am spending as little as possible on the #8 door stoppers.

 

If you want to spend as little as possible then set them aside & spend NOTHING. Spend your money wisely & build your engine right the first time instead of putting band-aids on inferior parts. The end product will cost more but you will be happier with its' performance & durability. Doing things over never saves money.

 

I get the point Dave, this build will be done right. Slight milling, 3 angle valve job, springs, retainers and any guide work would get priced. Procomp's might not cost much more. I have to decide on my direction, leaning towards the 403 stroker.

 

If you are going to get Pro Comp heads along with all the other new parts, I would go with a 455. I think you will be ahead of the game. I would hate to see you spend all that $ on a 403 and it not work out.

 

Jim, I have seen way too many failed 455 builds on these forums. I have 2 SBO cores to build, really like them. I will contact Dave's guy before I decide anything, he has built some impressive Olds for him. I will concentrate on the short block first. If it sits a year, so be it.