glamaina

Hello All,


My 72 Cutlass Supreme was my first car, had it for about 19 years now. Never really made any significant upgrades to it. however what I know about it at the bottom. Im looking to finally start making this thing move or at least get out of its own way. She is very slow right now, cant spin the tires etc.


My Goal:
-300ish HP
-Increase compression to something in the 9.5:1 ratio range(currently rated at 8.5:1)
-Keep it a street car, no plans to race it but still want it to scream pretty good. Want good low end, no need for a lot of power at high RPM as not planning on racing it.

My current plan:
- Determine the current gears (assuming stock 2.73)
- Determine if stock Cam
- Upgrade Pistons to Flat Tops,
- If necessary, upgrade Cam, Intake, Carb and gears to 3.42s with stall converter
-Hone and Bore the block (if necessary)


My questions would be:
Im getting conflicting information regarding cams and intakes.

A. Would there be a point in putting in the Edlebrock performer cam or would stock suffice for my goal? Perhaps the point would be just to freshen up a worn down cam with a near stock cam such as the performer.

Or Would something as powerful as the RPM or other high performance cam with an RPM intake be overkill for the street?

B. Also, the car came with a Holley Street Dominator Intake, which I believe is a single plane. I hear mixed reviews on these. Anyone have experience with this intake? Sounds like it would be more for high rpm situations.

C. Does anything need to be done to the Heads? Larger W30 valves? I am leaning towards my stock 7a heads being fine the way they are for my goal.

Thanks in advance


Current Car:
1972 Cutlass Supreme
Engine:350
4Brl Qjet
Stock 7a Heads
Upgrades:
Holley Street Dominator Intake
Dual Exhaust Headers
10 Bolt Posi Rear
Gears:Unknown (assuming stock)
Cam: Unknown (assuming stock)

70sgeek

I just completed an almost identical build. Used Sealed Pro L2320F flat tops, a Howards cam, E-brock 2711 intake, Qjet carb w/electric choke, stock rocker train setup and HEI ignition. Here's my prior thread. I'm in the process of breaking everything in but so far a great improvement over stock. Feels like I'm in that 300+ HP range though I haven't dyno'd it. I went with 3.08 gears though to avoid excessive RPMs on highway runs.


https://classicoldsmobile.com/forums...tml#post949416

glamaina

Fun71

The factory cam is very, very mild and you can get a lot more power with even an "RV" style cam without sacrificing the low end.

Factory cam is .400"/.400" lift, 250/264 advertised duration, 186º/204º duration @ .050" lift, 109º LSA. A generic 260º cam is way better than the factory cam, but if you are going with flat top pistons the engine will have enough compression to utilize something in the 215+ range.

I would recommend you figure out what compression the engine will have with the pistons and any head or block machine work intended, then talk to one of our resident engine builders or cam experts about a cam that will work with your overall package - engine, rear gears, and intended usage.

olds 307 and 403

Go with the LF2321 6cc dish pistons and something better than the Edelbrock Performer cam. I know Fun71 likes the cam in his signature, should be right up your alley and make the power you want. Cutlassefi is a great source for Olds cams. You just need a basic rebuild with the right upgrades for 300 HP.

glamaina

How driveable are your 3.42s? I just tested mine and turns out I have 3.23s. I was assuming I had stock because I have no low end. But now Im thinking it's just lack of HP.

olds 307 and 403

With a 2004R trans very driveable in my 88. With a 3 spd it was around 3000 rpm at 60 mph with short 245/60R14 tires. I would keep your current gearing. I am planning on 3.90 gears but with the 2004R in my 70. My 76 350 with milled #6 heads, thin head gaskets and a custom cam should hit 325 hp approximately. I would spend the extra on the new pistons Cutlassefi is making available, more money but a much better piston and ring pack.

BlackGold

If you have no low end -- especially with 3.23 gears -- then you need a tune-up, not a new engine. Learn to tune before you pour money into a rebuild. After all, if you do eventually rebuild it, you'll still need to tune it to get the most from it.

glamaina

I understand what you are saying but the owner prior to me was running nitrous through this thing and god knows for how long and what damage was done so I'm guessing there is more to do than a tune up. I want to open it up and see what's going on in there.

Fun71

I think if the N2O did any significant damage it would be obvious and not something subtle that would cause reduced low end power.

coppercutlass

Usually if nitrous is used improperly its not subtle.

Imo the street dominator intake would not be desirable for your build. I would sell it and buy a used RPM intake. Or even a performer. The performer works well under 5200 rpm.

You can make power with stock valves but chances are you will need new ones so yes the bigger 2 in. ( w30/w31 valves ) would be better.

I had a very mild combo composed of pretty much stock stuff that made a little over 300 hp. Ran 13.8's in the 1/4 mile and idled like stock but would roast the tires like no ones buisness.

It was a 73 350 with ( smaller ) dish pistons re ringed and polished crank and all that good stuff. with stock 72 7A heads stock rockers , performer intake , comp 260 h cam, 600 cfm carb , long tube headers , 2200 stall converter th400 and 3.42 gears. very basic build . ran awesome.