350 Refresh advice

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Old Jun 27, 2014 | 10:21 PM
  #1  
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350 Refresh advice

What I have is a 73 Supreme, Stock 350/350 4bbl, factory duel exhaust, 2:73. and about 80K miles. I will install new top, paint and new seals. I have done a complete rebuild on the front suspension, and will go through the brakes, so as to start out fresh. So on to the drive train. The car will spend most of its road time between 65 and 75 mph. So I am looking to make an interstate cruiser. As such I will keep the 2:73's. I would like to install a 2004R transmission. The Engine ran good when I parked it 2 years ago. It has been changed to HEI. It needs new gaskets, cleaned and painted. I was looking at changing the timing gears and chain, and upgrading the camshaft and lifters. I will be running a Quadrajet. I know we got some good engine guys here, so I was looking for cam recommendations (other parts or ideas welcome) that would work well for this set up.

Thanks in advance, Blane
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Old Jun 28, 2014 | 04:37 AM
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Sounds like a nice car...consider a compression test before any work is done to see if other work is needed and to get a look at the spark plugs. Would add valve seals to the list when doing the camshaft. If pulling the engine, install new freeze/expansion plugs and motor mounts also while it is out.

If the compression is good and it does not burn oil, I would not go into the bottom end of the engine.
Old Jun 28, 2014 | 05:52 AM
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If you plan on keeping the same compression ratio then I wouldn't change the cam, not much to gain there with low compression.
And if you're going with a 200-4R I'd change the gear to a 3.23 or so. That'll give you the best of both worlds, better acceleration and efficient cruising.
Old Jun 28, 2014 | 09:52 AM
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Originally Posted by Sugar Bear
Sounds like a nice car...consider a compression test before any work is done to see if other work is needed and to get a look at the spark plugs. Would add valve seals to the list when doing the camshaft. If pulling the engine, install new freeze/expansion plugs and motor mounts also while it is out.

If the compression is good and it does not burn oil, I would not go into the bottom end of the engine.
Thanks, The engine is going to come out. I will check compression for sure, sounds like a good idea on the rest. Car did not burn oil, plugs looked very good last time I had them out. I dont want to get into the bottom end.
Old Jun 28, 2014 | 10:44 AM
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Go 3.42 or higher for gearing. I run 1850 rpm at 60 mph with 3.42 gears and short 25.6" tires with a 2004R. Add a 2000 stall converter and it will accelerate much quicker and still purr on the highway. Get a quality timing set to replace the nylon original. New gaskets and seals, except head gaskets should do if your compression and oil pressure is good. I put in a performer can advanced two degrees and it works OK in my original 76 350, identical to your 350. That cam is pushing it and is a bit large for the low compression. I still have very strong low end, was launching at 1900 rpm, soon 2500 rpm.
Old Jun 28, 2014 | 11:01 AM
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I'd like to put an overdrive in my 74 cutlass but I'm not sure on whats going to happen with the center console shifter being its a three speed. Let us know how it goes.
Old Jun 28, 2014 | 11:40 AM
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Originally Posted by cutlassefi
If you plan on keeping the same compression ratio then I wouldn't change the cam, not much to gain there with low compression.
And if you're going with a 200-4R I'd change the gear to a 3.23 or so. That'll give you the best of both worlds, better acceleration and efficient cruising.
Just wondering if there would be a better cam for torque/gas mileage, right under 2000 rpm (should be about 75 mph with the OD trans)? Might it be a good idea to change out the 40 plus year old valve springs? This car will see a lot of highway miles. Long term it will get a 455, it will be in 7 or 8 years though, it will be my retirement fun project/present to myself. I have one from a 73 Delta 98 but water had gotten into one of the cylinders, and it has a small area of pitting, so I dont know if it can be bored or not. Anyway I dont have the $$ to trow at it right now.

Thanks again
Old Jun 28, 2014 | 11:51 AM
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Originally Posted by olds 307 and 403
Go 3.42 or higher for gearing. I run 1850 rpm at 60 mph with 3.42 gears and short 25.6" tires with a 2004R. Add a 2000 stall converter and it will accelerate much quicker and still purr on the highway. Get a quality timing set to replace the nylon original. New gaskets and seals, except head gaskets should do if your compression and oil pressure is good. I put in a performer can advanced two degrees and it works OK in my original 76 350, identical to your 350. That cam is pushing it and is a bit large for the low compression. I still have very strong low end, was launching at 1900 rpm, soon 2500 rpm.
I will be running a 26" tire, I'm looking to run 1850 at about 75 mph. Wide open straight roads around here, not many stop lights. Definitely going to do the timing set, and new gaskets/seals.

Thanks
Old Jun 28, 2014 | 11:59 AM
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Originally Posted by W30Olds
I'd like to put an overdrive in my 74 cutlass but I'm not sure on whats going to happen with the center console shifter being its a three speed. Let us know how it goes.
Good question. Anyone installed a 2004R in a 73-77 with center console?
Old Jun 28, 2014 | 10:16 PM
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Yes it would be a good idea to replace the valve springs. They are old, the engine may have sat for long periods with some springs fully compressed and the cam is going to be replaced.
Old Jun 29, 2014 | 02:03 PM
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Originally Posted by Sugar Bear
Yes it would be a good idea to replace the valve springs. They are old, the engine may have sat for long periods with some springs fully compressed and the cam is going to be replaced.
Kinda what I was thinking.
Old Jun 29, 2014 | 02:15 PM
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Have a look at www.shiftworks.com for a 4 speed conversion kit for your factory 3 speed console shifter. Their kits are nice and make it look like a factory 4 speed shifter.

If you really want a larger cam, think about swapping the #8 heads for some earlier 5, 6, 7, or 7a heads. Changing from the 80 cc original heads to 68 cc or so earlier heads will bump the compression up so you can effectively utilize the larger cam.

Last edited by Fun71; Jun 29, 2014 at 02:18 PM.
Old Jun 29, 2014 | 09:51 PM
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Originally Posted by Fun71
Have a look at www.shiftworks.com for a 4 speed conversion kit for your factory 3 speed console shifter. Their kits are nice and make it look like a factory 4 speed shifter.

If you really want a larger cam, think about swapping the #8 heads for some earlier 5, 6, 7, or 7a heads. Changing from the 80 cc original heads to 68 cc or so earlier heads will bump the compression up so you can effectively utilize the larger cam.
Thanks for the shifter link, thats what I was looking for. Thought about changing the heads, but I just want to freshen this one up, I plan on going with a 455 down the road, was just trying to maybe cam it toward mor low end torque for the overdrive at highway speeds.
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