Long story short, I inherited a bone stock 72 Cutlass Supreme with 120k on it over ten years ago and I'd like to refresh the engine. I have had several other fun cars that come and go, but the Olds means a lot to me and I've decided I will keep it, I'd just like it to be a little more fun to drive. I would like to keep the spirit of the car as original as possible while making improvements along the way. For example, I've replaced the manual drum brakes with power discs available from the period, and added an electric fan concealed in front of the radiator to supplement while idling in traffic.

For the engine, I'd like to be around 350 hp instead of 180. I want the engine to sound and feel powerful, but reliability and longevity are a priority. I understand the 68-70 cars were closer to this level from the factory just from different pistons making higher CR. I'm looking at the following parts along with rings, bearings, and seals/gaskets:

Speed Pro L2320F flat top pistons - CR around 10.25 with a thicker gasket?
Edelbrock 7112 Cam and lifters - 224/234 @.050 .496/.520 - do I need valve springs or rockers for the 7A heads at this level?
Edelbrock 7111 Performer RPM Intake
HEI
Holley Sniper EFI
Long tubes, 2.5" dual exhaust

The car currently falls on its face by 4k, that's what I'd like to remedy with the intake and cam, is running out to 6k doable? Is this combo so aggressive it will cause a big loss in drivability? I would go with the 2711 Performer intake and a different cam if so. I will occasionally go racing, but good vacuum and no headaches are more important to me than a tenth of ET.
Is there anything else I should be thinking about or looking into or considering before I head down this road?

 

Keep the 7111 intake and get a different cam. The edelbrock cam is not a great cam for your selected setup. The efi while nice isn't really cost effective over a well built Qjet.

 

Any suggestion on a different cam that would be better? Would like it to support up to 5500-6000 rpm without giving up much torque. I'd probably stick with a hydraulic flat tappet cam.

 

Is fuel available in your area for high compression? I'm guessing you'll need 93 octane with flat top pistons, someone please chime in that knows for sure.

 

Yes, I run ethanol free 93 already to help the fuel system survive long periods. I would continue to run premium at 10.25:1.

 

Good news...the HC engines sound awesome and get pretty good too!

 

Ditch the idea of the Speed pro pistons, old tech, better stuff available.
As mentioned Edelbrock cams are also old tech, newer grinds will offer more benefits.
And if you’re doing a Sniper, do timing control as well. You’ll be less restricted by octane because you can pull timing as it gets hot.
And finally, as much as I dislike the Sniper(Terminator X is way better), properly tuned it’ll run circles around ANY Qjet, guaranteed.

 

You will also need a higher stall torque converter with more cam. Definitely go with the Sniper 2 over the original and timing control, which isn't cheap but much cheaper than the Terminator X and SEFI. You need a steady higher psi fuel supply, I know a guy who had issues using an external fuel pump with the sniper. The Mahle 1mm ring pack 10.2cc pistons are nice but more money. If you 0 deck the block with Felpro heads gaskets and a clean up mill on the heads should give right around 9.5 to 1. Consider W31 valves and use the recommended springs to match whatever cam use choose. Cutlassefi should have a cam suggestion better than the RPM cam, 2500+ stall would be needed with it.

 

Okay, thanks for the info, all good suggestions! Any input on which pistons and cam would be better? If I can get to around 350hp without sacrificing reliability or drivability, that's the goal. Basically turning it back to a 1970 higher compression motor with better intake/exhaust and EFI. I'll definitely look into the Sniper 2 with timing control. I know the Terminator is better for all out performance, but the Sniper is a better fit for my budget, appearance, and adequate for performance. I will run the in-tank pump/sender module from Holley.

 

Hey, you're where I was in 1998! Get ready for one hell of a ride.
My very first build was flat top pistons, an "RV" cam, and just adding a second exhaust pipe. That alone was enough to wake it up and make it fun to drive. It was the stone age - we relied on the "Olds FAQ" and the "Performance Automotive Warehouse" printed catalog!

You're headed down the right path. Main thing is to figure out your budget then start trading things to see what you can actually afford. At this point I've built .... lord ... 4 engines, with each getting 3 or 4 rebuilds? It's addictive - once you get a little, then getting more sure seems like a good idea.

Your budget will limit how far you can go. Intake (performer RPM, definitely! the plan performer has almost no benefit over the stock) and exhaust are a must. It'll get much louder with the headers so make certain you're ready for that. Use Remflex exhaust gaskets!!

A higher stall converter can be useful even at a low level, and becomes pretty critical at higher levels. People will get into arguments about the precise best stall, but I just used a TCI Saturday Night Special in my TH350 when I had the 350 and it was excellent. Once you get more exciting, like my more recent stuff over 400hp (now over 500hp), then it's worthwhile to get a custom converter.

There's a few basic things you can do with the 7a heads. It's so expensive to rebuild heads now that it's almost cheaper to buy a new set - especially Procomp. Just note that Procomp heads really need to be examined and assembled by someone that knows that casting, e.g. Bernard Mondello. The Edelbrock is a nicer product, especially the current versions, and they have a small-block friendly version being released in the next few weeks, but it is much more expensive. If you stick with the 7a's then at least grind out the AIR bumps and do some basic bowl blend and cleanup. If the seats are in good shape and you're careful then you may not even need a valve job. Closing the exhaust crossover is, IMO, extremely important. The slugs from Edelbrock can "work", but they have a bad habit of coming loose and rattling. The better way is to fill with aluminum, but you're talking machine shop work and more money.

Your final compression ratio will also determine how far you can go with the cam. I put flat top pistons and stuck to the ~224 duration area with my 350 and it still had very good driving manners. If the budget won't cover pistons (remember that you're almost assuredly talking about boring/honing the block, mounting pistons, and balancing the rotating assembly once you get into the short block) then you'll want to stay in the 214 range (IMO). Switching to a roller cam is an excellent choice, but that comes with much more cost. You also have to set the clearance on a roller cam which isn't horribly complicated but can be time consuming to get it right. Hydraulic roller lifters are still hit-and-miss, so several of us are running solid roller lifters on a hydraulic roller cam. Works just fine. If you stick with flat tappet just pay extreme attention to the break-in. Try to make certain the car will fire up and run right away - use a known good carb and ignition system, have the cooling system filled, have some big fans to help cool it off, have enough gas, etc. Guys like Mark (cutlassefi) can help spec out an assembly that will work well together and package it up for you. If you want to stick to catalog stuff then I've always been a fan of the Lunati Voodoo grinds. I have a personal hatred for Comp grinds (I've run several over the years, hated all of them). But, cam preference is very personal.

The guys are right - ignition control is critical. I had tons of pinging problems with my early builds because getting a precise timing curve was really hard. I moved to a MSD 6al-2 programmable with a qjet and loved it. Now there's the Progression Ignition distributor which is extremely cool.

I've worked with only a couple of TBI systems and wasn't impressed. The tuning ability is very narrow so you can't do anything about a behavior you don't like. My buddy's Chevelle with an MSD Atomic dies while moving around parking lots and we're just stuck with it. You basically have to choose which rabbit hole to explore:
1) Carb tuning, which with a qjet is getting hard because part availability, especially secondary rods and hangers, is becoming scarce. I spent a couple of decades collecting cores and parts and eventually got a qjet setup that was fantastic, but it was a whole lot of work. You can switch to another platform like a Street Demon or a holley and have plenty of parts, but it's still an adventure to learn and tweak the various parts of the carb. I was limited on the top end with a Street Demon (450hp 403), and couldn't control fuel boiling on a Holley.
2) TBI and accept whatever limitations or quirks your system has. I would actually prefer to use a Progression Ignition distributor for timing control and not have the TBI do timing. This will cost a little more than a carb, but not a whole lot once you factor in all the parts and time to tune the carb. But with a carb you can keep changing things - eventually you run out of menu options on the TBI.
3) Multiport injection. Obviously a ton more cash and a ton more work, but you do get to do whatever you want at this point.

Note that fuel supply is critical any time you go injection. Uncovering the fuel pump will result in falling down, no matter what. You can go nuts like I did - a Tanks Inc tank, plus the Aeromotive Phantom module, plus the siphon for the Phantom, or just make certain to always have at least 1/3rd tank of gas.


Olds are not RPM monsters. Build for low end torque and make use of that. A basic 350 build should rev to 5500 pretty easily, but it'll run out of breath at that point. Your next stop might be the rear end. I assume you have the highway 2.73's. Moving to a deeper ratio and a limited slip (tons of different ways to do it) will completely change how the car feels, but you start losing cruising speed real fast. Here in TX you have to go 80mph or you get run over, hence I switch to an overdrive a while back.

Remember you'll need a new timing chain, a variety of gaskets, and all sorts of misc things you'll discover. My parts cost usually ended up being ~1.5x what I originally planned. Just like house renovations, there may be things you just don't want to know. If you're not prepared to replace/rebuild something then don't disturb it. Don't want to buy new bearings and grind the crank? Then don't disassemble the short block. Don't want to rebuild the trans? Don't open it!

I documented some of my adventure at https://cutlass.oddworld.org. There's been a lot done in the past few years but I got tired of documenting my failures.

 

Wow @oddball , what a wealth of good info! Sadly, looks like Lunati doesn't make cams for Olds anymore.
Based on what everyone had to say, here's a revised parts list, please give more input if needed:

Mahle PowerPak piston set 197815365 $771
Edelbrock Performer RPM 7111 $413
Holley Hyperspark II Kit 565-310K2 $816
Holley Sniper 2 550-510-3XX $1267
Holley fuel tank module 12-303 $429
Hedman Ceramic LT Headers 58063 $583
Jeg's Stainless 2.5" Dual Exhaust 30524 $448
Comp 218/224 475/480 110 cam, springs, lifters, timing set kit K42-222-4 $509
Bearings, gaskets, etc. $300ish
Machine work $500ish
Total budget $6000ish

I'll probably do in 3 stages, intake/exhaust first, then EFI/ignition, internals last.
I'll have the bores, deck, and crank checked and cleaned up. I'd like to avoid going into the heads at this point if it's not necessary. I would also like to leave the rear end alone as I can't see sinking any money into the 8.2" right now instead of saving up for a complete 12 bolt with 3.31s?

 

For the Holley stuff, they have multiple sales throughout the year, buy it then. My SEFI was still 4K. You will need valve springs and do valve seals at that point, consider that the bare minimum for heads. I would do a compression test to make sure the valves are sealing as is. How many miles are on this motor?

 

X2 olds 307 and 403...start with a compression test. If the results are questionable do a leak down test.

 

120k on the car, about 2k since 1989.

 

Eh?? An 8.2?? It really should have the Olds 8.5". Standard GM Corporate 8.5" internals, but bolt-in axles. There's some confusing info out there that makes it sound like 8.2's came on (some of?) these cars, but it's most likely an 8.5. This was kind of an odd time as GM was consolidating rear end designs and moving towards the 8.2 in the later cars. The bolt-in axle variants were uncommon, compared to Chevy, so Olds stuff gets treated just like an Olds engine - start talking about 70's GM stuff and everyone assumes Chevy.

That fuel pump must be relatively new, I don't remember seeing it. That's definitely the easiest way to go and should be fairly reliable. The mat is small so it'll only have a moment's worth of fuel, but it's better than nothing. It's unfortunate that it just has a basic barb outlet - be certain to use fuel injection clamps!

As for Lunati: @#$%@#$ corporate consolidation.