Im looking for opinions on a build im researching. Im going to be starting a new project in the fall after i build my new pole barn and house this summer so im trying to get things sorted out before im too busy. Im looking to retire the 72 from road trip duty so i will be purchasing a 64 that i will be putting a 350 and the 2004r trans in along with a 3.42 gear and around a 2000 or so converter. What im looking for is a car that is comfortable, reliable, and still have good power for passing on highway, and of course the occasional burnout. I have the stock 350 that was in the 72 to use as a core. Im open to suggestions as far as cubic inch, heads, intake, cam, etc. Im looking for a package that is efficiant not just max power at a givin rpm. With that said im not going to throw any numbers out as far as budget and hp/tq goes. Im not looking for an all forged aluminuim headed race motor but more of a package that makes good usable power at 2000 to 4500 rpm. Id like to find power in more ways than just bigger heads, cam, etc. Like using coated bearings, keeping friction to a minimuim, keeping windage down etc. I want to discuss different build ideas and how to keep the engine efficient at making power without building more engine than i need but not a stock rebuild either. I dont mind buying expensive parts as long as they make sense and help me achieve my goals. With that said i dont want to spend good money on parts just because they are shiny. I would like to top it off with a qjet to start with because i really want to learn to tune these carbs and know a guy that is very good with them that will give me guidance but will eventually switch to fuel injection. Any input is appreciated thanks.

 

I had a 9 to 1 355, stock valve sizes, street port job, 16-18 Engle cam (210/216 .472/.488) 2600 Coan converter, 3.42 gears in an 83 Cutlass wagan. Very fun to drive, smooth idle, reliable, plenty of low end torque and throttle response and ran a high 13. That was a nice, prectical street combo that would be very easy to duplicate.

 

Thin piston ring packs are a good idea. They add hp/tq and no doubt help fuel economy. Probably 400 sbc Hyper pistons with the 1/16, 1/16, 3/16" ring packs with the right length sbc rods is a good way to go. Lighter and stronger than original plus can have tighter piston to bore compared to a forged piston. Just match the dish to your desired compression ratio.

 

Headers, H pipe, I'd go alumimun heads milled down and performer intake with 10:1 compression. I was told the hypereutectic pistons were lighter than cast and forged. Roller cam, roller rockers. Aluminum water pump, windage tray. This woud do you better than 21mpg and still have good power.

 

I don't agree. I can't see a cam that fits this combo getting 21 mpg. Don't know how you can make a blanket statement like that. Besides, he would have $7500 in it, he does not need to in order to rech his goals.

 

I had a 9 to 1 350 it was a refreshed 73 350 with 14cc pistons , 72 7a heads refreshed stock valves no bowl work, stock rockers, edelbrock perfromer intake , eddy 600 cfm carb , full length headers, proform hei , x pipe with hooker aero chambers, th400 with 2200 stall and 3.73's . When the car was all steel it ran 13.86. I had maual steering and all my passes where through the mufflers. Probaly could have gone a bit faster with a th350. I was gettin about 15 mpg on the highway at 55 mph and 10 in the city.

Edit I was running a comp 260h cam

 

I'm going to hit the "hornet nest" with a stick. I would find a 403 short block. Jmo, Ken

 

My 72 Cutlass Supreme with stock 350 4bbl with headers got 20mpg. He should reach that plus some with a better combo.
Here's a crane cam. You think that's too much lift?
Excellent low end torque, good idle, daily usage, towing,
performance and fuel efficiency, 2600-3000 cruise RPM,
8.75 to 10.5 compression ratio advised.
HR-214/325-2S-12 IG
He didnt mention money. I figured he could take the info and go with the parts he wanted.

 

I beg to differ on the fuel economy. A STOCK engine might see 20 mpg but I think once you start tinkering with performance you start to sacrifice mpg in order to get the performance which is usually the case. Running a q jet would probably help . You supreme might have had a more fuel friendly gear.

 

??

I had a bone stock 1970 Cutlass Supreme, 350-4bbl with headers and 2.56 rear gears and it never got anywhere near 20 MPG in the nearly 20 years I drove it (1977 to early 90s).

When I graduated from college, I drove it 60 miles each way to work so I tried to maximize economy by installing taller tires (215-75-15s) and reducing the primary jet sizes. The best I ever got was 16 MPG with steady 60 MPH cruising on a flat 2 lane highway.

I have often heard over the years that folks with the 2bbl engines got upper teens to 20 MPG and this has been attributed to those cars having a slightly smaller camshaft than the 4bbl engines, but so far I haven't seen the cam specs to back that up. All I have seen are the "replacement" cam specs that show the same cam for all the 350 auto engines.

 

I ran a 2.73 gear. He will be running at 3.42 with overdrive. He will actually be running lower RPM’s.

Same car with my stock 455 with a 456/478 lift cam, 10:1, exhaust ports welded flush, crossover welded but not filled, headers, edelbrock 750, cast iron intake TH400 w/2.73 gears got 15 mpg highway.

Rebuilt the motor .490 lift 230 dur cam, 9.7:1 same heads but pocket ported, roller rockers, headers, quadrajet, performer intake, TH400 w/2.73 gears gets 15mpg highway and I plan to exceed that with some quadrajet tuning, 3.73 w/overdrive.

Back to the 350 build, going from 8.5:1 to 10:1 should make better use of the same fuel. Aluminum intake and heads would drop almost 100lbs off the car and run more efficiently. Roller cam and roller rockers would increase efficiency with less friction. Whether or not a roller cam will dump too much fuel is a possibility. Lighter pistons would make the motor run more efficient also. I guess I don’t see it as being impossible to get 21mpg.

 

Fun71 I'll add that my girlfriends bone stock 79 TA w/403 gets 16 mpg. Did it twice at 75mph this winter.

 

I got 12 mpg with that same 490 cam from comp 10 to 1 compression and 3.73 gears behind an th400 with full length headers and a eddy 600 cfm carb. Very similad build to yours at the time but an sbo now I have more cam and it actually runs much better went .030 over and still get 12 ish mpg

 

Again, IMO, no way he is getting 20 MPG with that cam and a 10 to 1 355. Will it run good? Heck yeah, but the OP asked for a combination to maximize economy while have decent performance, and a 10 to 1 engine with a .520 lift cam really doesn't fit the bill. IMHO.

This is what he stated,
"Im not looking for an all forged aluminuim headed race motor but more of a package that makes good usable power at 2000 to 4500 rpm."

 

Agree with Jim, 10 to 1 will require too large of a cam for fuel economy, especially with iron heads. He should aim for low to mid 9's compression, depending on the fuel available and what he wants to run. Procomp heads might work with minor milling, supposedly very good velocity and better chamber, 10 to 1 might work better with them. Roller cams is another reason modern engines perform. I think the Olds 307 was the only engine that switched to a roller and lost performance. That had less to do with the cam, other changes crippled it. Less compression, tiny ports and a roller cam with less lift than the flat tappet it replaced, was reason for the power drop.

 

Budget isnt the main priority here i will pay what it costs for the results im looking for. And as far as economy goes im looking to build an engine that makes good power for the amount of fuel it uses. I have gotten 15 with my big block i would think 18 mpg would be a good goal as long as the car still has some power. I like the idea of a more modern piston and ring combo to reduce friction as thats the kind of ideas im looking for. I would like to free up as much power as i can and then look into a roller cam and some head work. I believe finding the optimal cam to operate in the range im looking for will actually have better efficancy or am i wrong?

 

You are on the right track I'd just do a super good rebuild, do as much blueprinting as possible to get things as close to perfect as possible, stay with a pretty small cam maybe even a baby roller cam, use a spread bore carb of some sort, headers on a 64 are pretty expensive only a couple of companies make them, keep the compression down so you don't have to worry about every tank full of gas you put in.
If you can get a dependable 300HP out of the engine it will do everything you want and still get good milage.
You are doing the same thing I did except I used a 3:90 gear, and I put to much compression in and now I have a big PITA job to fix it.

 

Your going to have to do this with a lot of thought to your trans and final drive gear. I would look into a BBO and a 2 barrel. Build it for lot's of low rpm torque.

 

BBO with a 2BBL ????? That's different.

 

Make a torquey sipper.

 

That's kinda like a few sips of Jack and a lot of Jill

 

I already have a big block car and i think the extra weight wouldnt help things. What about a stroker for the midrange torque im after? What would be the optimum compression for efficiancy and power?

 

I think unless you are building a race engine a stroker is pretty pointless not trying to be rude jmo. I would do a 403 before a stroker for the fact you plan on keeping the rpms down and the cubes are already there.

 

Not much weight difference between a SBO and a BBO

 

I think its actually 50 lbs or something like that.

 

A 403 with .024" KB Hyper pistons which have the 1/16, 1/16, 3/16" ring pack, roller cam with unmilled Procomp heads(assuming 84 cc) with .040" Mr Gasket MLS 4.410" bore head gaskets and 0 deck give 9.3 to 1. Even at 82 cc, it would give 9.5 to 1, perfect pump gas ratio, especially with aluminum heads. Something to consider.

 

Oldsmoboogie- I was thinking of putting a 383 Stroker in my 72 Cutlass... I don't know if you have looked into that..

 

More cubic inches is going to use more fuel. You can get the power out of a 350. Also I dont think 10:1 with aluminum heads is too much compression.

 

This makes absolutely no sense to me. No matter what size the engine, it takes more fuel to make more power, all things being equal.

 

So in your mind a 455 should get the same gas mileage as a 350 or even a 260?

 

A 350 will get the job done. My 350 with a 2004r and a 3:90 gear climbs mountains like they aren't even there.

 

The 350 and 403 are close mileage wise. A stroker 350 could be mild and out power a much hotter 350. Less compression and cam would help mileage. Build a mid 9 to 1 374 or 380 with aluminum heads or ported cast iron and have fun.

 

My 455 running SBO heads with a 4barrel, BBO manifolds through a TH350 and a 2.56 rear gets 19MPG all day if I keep my foot out of it. Still plenty of torque to get the car up going when I want it too. My SBO low compression with 8 heads, 4 barrel, manifolds, 700R4 with the 2.56 rear gets 25mpg all day. Its not quick off the line but still fun. I'm upgrading the rear to a 3.42 posi which will help fun factor and still get good mileage with the OD. Just switching to flat top pistons, running iron 5,6,7 heads and getting compression to around 9.5, 4 barrel with qjet and you will be fine for torque and power. Don't spend more than you have to.

 

I'm not going to argue with you, I just disagree with just about everything you posted in this thread. You are not reading what the OP is looking for.

 

I am not saying you are being untruthful, but I have never heard of anyone getting those kinds of numbers. If you really did, great job!

 

Sorry but I don't believe that. My 05 Deville with much more efficient Northstar engine(DOHC 32 valves) gets 22mpg all freeway(it's my commuter), my wife's Honda Accord with V6 gets about 26mpg, When my 350 in my Cutlass was stock I was getting about 16-18 with 2bbl. After rebuild 12-14 if I am not stepping on it.
I think your math is wrong.

@Alex72Cutty I have a 383 stroker in my 69 Chevelle and it's a mighty engine, it can't mess with nicely build BBO but it will smoke most of the SBO, however it takes a lot more than most people think to put it in Olds. In the end cost wise you are better off buying/building a mild 455 and keeping it Olds.
If your budget allows look into a LS.
Fuel economy and power.

 

Sorry to be debbie downer here, but 2bbls are actually worse for mileage going around town. TRUE, The 2 bbl carbs have no secondaries, but the primaries are much bigger than the 4bbl qjet primaries. 4 bbl qjets use less fuel when the secondaries are not open. Once you hammer it though, those secondaries are pretty large.

 

I think With 2.56 gears those secondaries are open more often then not.

 

Thanks for the input but i already have an ls equiped car. The 64 will stay all oldsmobile. Whats involved in building a stroker sbo?

 

I still say, get a 403 Olds with a quadrajet. It's better fuel economy than a 2 barrel unless you open the back "large" barrels. Your trying to reinvent the wheel. Go with what is already available and much cheaper. Jmo, Ken