350 rocket performance suggestions

Old February 13th, 2019, 11:48 AM
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350 rocket performance suggestions

I am in the process of restoring a 1972 cutlass S and would like some suggestions on performance upgrades. I am not interested in changing the engine and would like to avoid doing an engine rebuild unless I have problems later on. When I bought the car I was told it has high energy ignition and a mild cam. I know that doesn't tell you much but that's what I know at this point. I did buy a 4 barrel quadrajet carb for the car which I have installed, running stock 14" wheels with 245/60r14 BF goodrich radial TA tires and I have 3.73 gears to install. I would love to get as much acceleration power as possible so I am looking for some suggestions on headers, which stall converter would work best with the gears and any other performance upgrades you would suggest. I will not be racing with the car but just want to experience more power than the stock 350 will produce. Any suggestions would be greatly appreciated.
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Old February 13th, 2019, 01:52 PM
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What carb was on it before? If it had a 2v, probably no cam was changed, the hi energy coil does nothing for performance. The best bang for your buck would be gears and dual exhaust.
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Old February 13th, 2019, 04:06 PM
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Agreed on the duals and gears. I'd do those and ensure the tune is perfect, then stop there.

The factory engine is very low compression, like 8:1 if it still has the original thin head gaskets, so you have to be careful when changing the camshaft. The low compression ratio won't support much of an increase, so it's easy to overcam the engine and actually decrease performance.
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Old February 13th, 2019, 06:37 PM
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Find some earlier heads with smaller chambers, mill the crap out of the heads you have, make sure the carb and ignition is dialed in, install a mild converter, and have fun. Of you want more than that, look into a 200R4 trans swap. Lower first gear, and overdrive. Best of both worlds.
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Old February 14th, 2019, 08:21 AM
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What is your budget? Where do you mostly drive? In town or highway driving?
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Old March 12th, 2019, 07:46 AM
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It had a stock 2 barrel carb on it before changing.
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Old March 12th, 2019, 07:50 AM
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Originally Posted by olds 307 and 403 View Post
What is your budget? Where do you mostly drive? In town or highway driving?
I haven't really set a budget for the project and just working on it a little as I get extra to spend. I would say the majority of my driving would be in town driving at speeds up to 45-50 range. I may drive the car to work some which would require me to get up to speeds as high as 65-70 to keep up with traffic.
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Old March 12th, 2019, 09:14 AM
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Originally Posted by Svu0312 View Post
It had a stock 2 barrel carb on it before changing.
The 2bbl and 4bbl engines had the same compression ratio, used the same heads, and had the same camshaft, but that doesn't matter since yours has an aftermarket cam now.

Install the 3.73 gears.
I like Heddman Headers and have used them on both my 70 Supreme 350 and on the 71 convertible 350.
I currently have a Hughes Performance 2500 RPM converter but it is matched to the UltraDyne camshaft, so your engine may not need as much stall with the cam you have. It really depends upon the camshaft. I would recommend installing a tach, then do a WOT run from a dead stop and see at what RPM the engine starts really pulling. That will give you an idea of the stall RPM that matches the engine. If the engine hs a mild RV cam, then a 2000-2200 RPM converter may be good for it.
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Old March 14th, 2019, 08:26 PM
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I ran a 350 in my 72 cutlass s with a very basic near stock build but it ran very well at the track 13.86 in the 1/4 mile and was a very fun street engine. My build consisted of a stock freshened up 73 350 w/ the smaller 14cc dished pistons. for 71/72 the low compression engines got toilet bowls for pistons. 68-70 had 14 cc dishes as did 73- ? I wanna say late 70's. If you use your stock heads and have them milled and use some thin replacement head gaskets you can get your compression around 9 to 1. I used a comp 260 h cam which is more or less a towing cam . I had an edelbrock performer intake , I used stock valvetrain components, double roller timing chain, an HEI distributor, edelbrock 1405 600 cfm carb, full length blackjacks headers (old 70's headers) , with a th400 and 2400 stall converter and 3.73 gears. It was sweet and simple. I also did not have power steering or a/c. those things eat a bit of power but on the street wont matter. what will help you big time will be the rear end gear and fresh trans with more ideal components like more aggressive clutches and a shift kit. I would do those first. I had a 307 in my 72 when I blew up one of my hotter 350's and it was a really fun street car. It had the same th400 and 2400 stall and 3.73 gears and it would lay some serious rubber from a stand still flat footing the gas.

current 355 olds is tad more than most would want for a street engine with a solid lifter cam and 3.90's with a 3500 stall cruising down the highway at 4000 rpm. she screams but to me its still a street car. "street" now a days is a vauge definition lol.

Last edited by coppercutlass; March 14th, 2019 at 08:36 PM.
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Old March 15th, 2019, 06:08 AM
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If it has the 204/214 cam, performance will be Ok but as said it is probably stock. One thing I would check is the timing chain and gears. The factory cam gear is nylon coated, it can fall apart and get sucked into the oil pump pickup. I would say the base Summit or Jegs torque converter will stall around 2000 rpm, much better than the stock 1600 rpm. The gears, converter, headers and dual exhaust in that order for launch help.
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Old March 16th, 2019, 08:16 AM
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[QUOTE=Fun71;1154461]Agreed on the duals and gears. I'd do those and ensure the tune is perfect, then stop there.

^^^^^^ X2 ^^^^^^^^ I couldn't agree more.

Most of us started where you are. A budget is difficult to nail down at the beginning, especially if the engine runs good and cruises nicely. Power is always something we want at times, however it does come with a greater cost with Olds vs Chev engines. I myself, kicked things around for years trying to come up things to spend money on rather than a complete rebuild because it ran so well. I chose to go the eye candy route to keep myself busy, going to shows and working on the car. I have done little bolt on's that made me happy until I couldn't go any further. This took a few years.
I spent money to lighten the car up, such as and intake, mini starter, aluminium calipers, rad, etc. Even thou, the intake, starter etc doesn't net much gain with a stock engine, it certainly takes some weight off the car.
The rear gears, duals and tune will certainly get you headed in a good direction to start .

Eric
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Old March 16th, 2019, 09:30 AM
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I started exactly where you were - stock 350 2bbl in my '72 ragtop - fully rebuilt the motor out with main pieces to include an E-brock intake, Howards street performer cam, forged flat top pistons, Cloyes billet double roller chain and an 800 electric choke Qjet built to the engine specs. Retained and fully rebuilt the stock 7a heads, slightly surface milled and set up for unleaded fuel. The TH350 is mated to a 2300-2600 stall converter and 3.08 posi on 245-60-15 wheels. Compression now is 9.5:1 and I run 92-3 pump gas.

Exhaust is straight 2.25" duals with Flowmaster 40's.

3.08 gears are a good street/highway compromise - I had 3.23 gears in a prior Skylark and RPM's were well over 3k by the time I hit 65mph on the same size tires. With 3.08 I still have a pretty strong pull from idle all the way up to highway speeds and RPM's are still livable as the speed climbs.
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Old March 17th, 2019, 03:57 AM
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Yep, Long tube headers and gears will give you the most. Then, maybe a Performer RPM intake. Keep in mind if you touch the cylinder heads, the gaskets that are on there are only .017" thick. Fel Pro replacements are .041" thick so unless you contact Smitty for a set of his .011" head gaskets at $140 (Reusable though), you would need to mill .024" just to get back where you were and pick up nothing. Your heads are fine, the pistons are the problem, if there is one.
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Old March 17th, 2019, 06:59 AM
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Originally Posted by brownbomber77 View Post
unless you contact Smitty for a set of his .011" head gaskets at $140
Are these gaskets still available?
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Old March 17th, 2019, 08:56 PM
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[QUOTE=Svu0312;1159668]I haven't really set a budget for the project and just working on it a little as I get extra to spend.

I would add a Trans-go shift kit with a new vacuum modulator as well. You will like the feel of a nice quick shift rather than the lazy factory shift. That would also be money well spent IMO.


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Old March 18th, 2019, 03:21 AM
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Originally Posted by young olds View Post


Are these gaskets still available?
Yes, you'll have to contact him on Facebook at M&J Performance or
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Old March 19th, 2019, 10:44 AM
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I would be careful smitty has been up and down. he was selling his car and had moved to Tennessee and some customers had zero contact about their engines
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Old March 19th, 2019, 01:58 PM
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Originally Posted by coppercutlass View Post
I would be careful smitty has been up and down. he was selling his car and had moved to Tennessee and some customers had zero contact about their engines
Yeah I wasn’t going to say anything but now that you’ve opened that can of worms.......
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Old March 19th, 2019, 04:49 PM
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Who's this Smitty?
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Old March 19th, 2019, 06:07 PM
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Originally Posted by VORTECPRO View Post
Who's this Smitty?
See post number 16 . He went MIA for a while and didn't bother following up with customer engines he had taken on to build. Left several hangin'

Mark (Cutlassefi ) has taken care of many here and is the go to guy for our Olds engine builds.

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Old March 23rd, 2019, 05:30 AM
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Sooooooo......Mark are you taking over his head gasket inventory?? haha. I wasn't aware of any woes with him, he shipped my head gaskets pretty quick a couple years ago.
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Old March 23rd, 2019, 08:24 AM
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You can.buy the readily available .028 cortecos from RRP. Skim the heads and I belive the cortecos are reuseable but dont quote me on that.
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Old March 23rd, 2019, 11:10 AM
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Originally Posted by VORTECPRO View Post
Who's this Smitty?
Who are you?
Just wondering, how is this question helpful to the OP .

Eric
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Old March 23rd, 2019, 01:13 PM
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Helps the OP avoid smitty
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Old March 23rd, 2019, 04:55 PM
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Originally Posted by 76olds View Post
Who are you?
Just wondering, how is this question helpful to the OP .

Eric
A person wanting to know who Smitty is. I did some research, I like his car.
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Old March 23rd, 2019, 06:54 PM
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He is selling his car
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Old March 23rd, 2019, 06:55 PM
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Originally Posted by coppercutlass View Post
He is selling his car
How's that car run?
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Old March 23rd, 2019, 08:49 PM
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Solid low 10 sec car full bulk I belive
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Old March 31st, 2019, 12:47 PM
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Smitty

. . . . . . . . . . and a can of worms was very generous of you Cutlassefi. Thanks for your help and always being available to me and countless others.

George, in south Alabama
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