TAC Tech => Mechanical => Topic started by: TA Dave on May 31, 2021, 03:14:01 PM
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Hello TAC -
I just looked up the block casting number on my Olds 403 in my 1979 Trans Am and found out that I actually have an Olds 350!
I have been spending a lot of time looking at how to make the 403 "streetable" but now that I find I have a 350, I am at a loss. Is the Olds 350 a good engine? I suspect it has the same durability as a 403...so many of the same parts.
Should I find a 403 block and do to it what I was planning to to all along? I know the 403 was weak, but I will be driving it, not racing it - and it should be good for some minor street racing, but nothing extreme. Plus my "donor" 350 gives me a lot of the parts I would have had to seek out for the "streetable" 403 anyway (heads & crank) - this keeps my costs lower.
Or should I try to find a Poncho or do a SBC swap?
I'm looking for opinions...what are your thoughts?
Also - worth noting is that I chose not to do an LS-swap because the Olds 403 was more interesting.
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My first car, a 69 Cutlass S had a 350 - it would stomp my friend's 350 Nova hard, even with 2.56's. It was originally a 2 barrel car converted to 4 and dual exhaust added - nothing else.
The early blocks are high nickel pieces - if you are staying carb I would build it, if not go LS.
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The 403 wasn't weak enough for most guys on the street, 350 Olds isn't much different, smaller capacity. As mentioned, earlier blocks are also stronger so depends what it came out of and what you plans were, it may not affect it at all. Otherwise, with all the guys going the LS route recently, ie no longer more interesting, there'd be a few 403, or other decent engines sitting around, stock or built beyond what it would cost to even look at your existing block, even if it were a 403.
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The Olds 350 has the ability to go to 434 cubes stroked. There is now a 4inch stroker crank.
If you have a 68-72 Block those are solid main blocks. One of the better blocks Oldsmobile made. Put in the stroker crank, LS rods, and the Mahle pistons and will zoom to 500 HP without much. We did 480 hp out of the box on carb before any tunes.
You can buy the kit from Mark Remmel at https://newoldsperformance.com/
Most 403s I have done came around 400-450HP with a lot of cam and head work.
Sure you can get a junkyard LS and probably most economical way to go. Texas speed is about 10 miles from me which does a lot of LS work. We looked at them and they are about 15K for their 540HP LS. GM 376 LS is right around 9K before the ECU and other mods. Just depends on your goals as the LS will be full EFi/computer/coil on plug.
The link below is a 68-72 Small block Olds bored to 4.155 and stuffed with stroker crank and we modeled it after a LS build and full on computer/Efi.
Picture below. Under the rag is a wilson 4150 EFI Body 1287 CFM.
http://transamcountry.com/community/index.php?topic=83645.0
(https://live.staticflickr.com/65535/51220260110_b9bb67f02a_k.jpg) (https://flic.kr/p/2m3adQW)07956CE5-287F-4FA0-9469-D247034FB372 (https://flic.kr/p/2m3adQW) by Michael Gabel (https://www.flickr.com/photos/107205487@N06/), on Flickr
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Here are some thoughts......
I do have quite a bit of olds parts from all my past builds and heads that maybe of interest for your 350/403 of the future. This is what I have and will sell.
330 offset ground crank 3.485 with matched chevy 2” main 927 rod pin aluminum rods. Came out of good motor. Screamer for a 350 and that is where it came from. Will take you out to 377 or so depending on your bore of pistons. Will need custom pistons. race tec / CP pistons. Crank is good to go. You need a 350 stroker piston 4.125 x 3.500 stroke x 6.000 Chevrolet 2" rod .927 pin. Have the balancer and flexplate. You can do in 403.
330 crank as pulled. Not rusted. Coated in thick grease.
1967 Olds #4 small block heads. These are good cores. Will need machine work/valves springs. One set bare. One set take offs.
Edelbrock OLDS gen 1 big block heads. Machined/flowed. Some port work. These are at champion racing. Need valves/springs to match cam/engine as needed. Use with the heads RPM intake.
All of these parts are nothing i would not hesitate to use myself. Nothing i do is cheap.
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As mentioned above, 350's vary in strength, and in fact some of the 350's had windowed webs like a 403, so it really depends on what year you have whether you want to consider a big build-out. I was thinking the windowed webs started in 1976 but from google it looks like maybe 77. You be the judge. Olds403 is much more expert than I am.
They have plenty of power to cruise around with. I'm not sure what you really want in the eternal question of $$$/mph. I am sure you can still find a 403 for sale once in a while if you prefer.
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Joe, the 68-72's are the best small block Olds motors in my opinion. 330's in 67 were decent and you can bore them a bit too. If money isn't an issue use a diesel block D or Dx. I nearly went Dx, but it was either put more power into the motor or build out the EFI using the gas block. Host of other issues come up using the D/Dx and its a heavy motor too. If I was going to race the car and not be a driver the D/DX is the way to go, but with the new Rocket racing big block with CGI there was no logic into building anything more than putting stroker crank in the 350 early block. I've ran 403's for a long time and nothing bad to say about them - never broke one. They too are harder to find now. With the cat out of the bag - I expect to see more stroked small block olds. I have so much left over olds parts that I will never use.
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Wow, I couldn't give away a nice running pull out 403 a couple years ago. Sold it for $400 with the TH350 trans
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FormTA
Fair price. For what you sold. A maxed out 403 shortblock is 4 to 5k. Built several and may sell my spare with forged crank/floating rods/custom piston metric rings with Girdle. Solid 12 second build
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Thanks everyone! I have been learning a lot in the last week or two. I have decided to build the 350 Olds. It will be a unique interest piece and probably give me all the power I want.
Dave
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TA Dave,
Glad you’re going ahead with the 350 Olds build. Back in the early 70’s I had a lot of friends with good running Olds. One had a 70 442, another with a 70 W-30 442, one with a W-31 Cutlass, a girlfriend with a 69 442 that I really enjoyed driving. I also helped a buddy with a 1972 Indy Pace car, it came with a low compression 455. We pulled the engine out when the car was only a week old and had custom made forged Venolia pistons to raise the compression up to 10.5-1. There used to be a guy by the name of Joe Mondello out of California, he really knew how to get power out of an Olds.
Since lots of TA’s came with Olds engines it’s nice to see you build one.
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5th T/A. - Joe Mondello passed away in 2011. His son Bernard and I have talked a few times and such. We have picture of Joe in the 90's with my brother at his place in Paso Robles.
Bernard only does heads now and such. He has a shop called https://bernardmondelloracing.com
Lynn owns Mondello now and that legacy. The 424 stroker 403 I did in 2019 was supplied with parts from Mark Remmel on classicoldsperformance and we machined the block here, but rest came from Mark including the stroked 330 crank. The LS Olds / Stroker is a full custom build that Mark did as well. Besides Mark there are few other Olds builders and suppliers, but Mark has the stroker small block cranks that no one else has.
Like I posted above I have quite a bit of small block Olds parts and rather see them used than sit here. Just email me if anyone is looking for something.
Sigtauswt@yahoo.com
Mike
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My question is why would yo want a stroker crank? Part of the strength of the 330/350 is it's short stroke/large bore and high revving ability. To me Olds lost their way when they went to long stroke engines like the 68,69 400 and 455.
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Scarebird, the Olds stroker crank is nearly identical to that of the LS crank. Its a 4inch stroke crank in place of the stock 3.385 stroke on a 6 inch rod. The only difference is that it has the journals for the Olds and the counterweights. I used 6.125 LS rods and LS pistons which is similar to the LS7 427 and nearly the same in terms of bore/stroke. We are are now at 428 cubes if my math is right on a 4.155 bore. Its close the same specs as a BB, but under the bore and stroke by .25 or so. I have photos that the crank clears everything with no mods. Yes...its close to the walls of the block with the crank weigths, but it fits.....
it's no different that what Butler did with the 350/400 Pontiac motors. When you say high reving what do you mean ? I have 40 dyno pulls and can tell you that the motor runs out guts at 5500 RPM. You can't flow enough air through the RPM intake and Big Block heads to make any more power. You can rev it - sure, but It won't make more power. It's out a juice because Olds doesn't have a head that flows above 300CFM - they do but you are in all out race mode. The crank is billet and if my memory is correct its 42 lbs. Lighter than the stock 350 and lighter than LS and internally balanced. I have the last dyno run video and more than willing to share/post the video and any dyno sheets and all the ECU data. These stroker cranks will put the Olds in place where it was not in the past. In the past, Either we sent cranks to Ohio crank shaft to be lighten/stroked or just used longer rods and shorter pistons. I've done all of those. This crank is something special for the small block guys. We will have heads later this year too for Small blocks.
Either way my final pull was today and did 509Hp/535tq out a gas block 350 olds. :shock: I totally respect the comments and appreciated. All the questions - let me know as over the last three years learned a ton.