devmar07

What can I do myself to get some more power I have a 72 cutlass s with 350. The engine has performer intake, Holley 650 carb, flow tech headers that dump into
Flowmaster exhaust, hei distributor. Not sure of internal comp was rebuilt when I bought the car I do know that the 7a heads where replaced with #8 garbage. I am more of a parts changer but a challenge would be nice

455man

What gears are you running? I'll assume a TH350 with a stock converter? How far are you wanting to go? Cam? Heads? How many ponies do you want?

M-14

Some tuning on the parts that you have would help. Any type of bogging, hesitation, or spark knock?

devmar07

I would like to do at least some decent heads for better compression if I don't have to be an engine builder, any suggestion on heads that would be good for my current setup. I built the entire car, it was bought in pieces so I can handle almost anything but changing out a cam seems tough. I shamefully don't know what gears I'm running. And it does have the th350

devmar07

Actually the motor runs great I have it timed 18degrees advanced it has decent power in
3rd but can't seem to get out of its own way at first

captjim

"Rebuilt" is a subjective term, but if stock or stock replacement pistons were used along with #8 heads (which aren't "garbage") your compression is going to be VERY low, like mid 7.xx to 1. You need to find out what pistons are in there.

71supreme

Believe it or not, your best bang for the buck is to be sure what rear ratio you have. There is a code on the Pass side of your rear axle housing. Post it, and I am sure someone here with a service manual for the 72 can tell you what the ratio is. I was sad to learn mine was just 2.56 IIRC, a bump to 3.08 gears via a rearend swap would really wake that 350 up!

coppercutlass

I think a 3.42 would be perfect . if you dont mind higher rpm driving a 3.73 is the best all around gear for street and strip. Is there any way you can look inside the cylinder and see what kind of pistons it has. sometimes you csan tell by the dish or lack of.

devmar07

The only time I saw the piston was when I set the tic for the hei install and they just looked flat. I will also check the
Gearing tomorrow and post it

devmar07

Pretty sure #8s are smog heads aren't they

coppercutlass

Yes 8 heads are smog heads but they are ideal for a flat top piston build with a 0 deck height and .040 head gasket you are at 9 to 1 . For a nice street strip cruiser they will be sufficent. If they look flat make sure because you ciuld just be looking at the face of the dish. Find a buddy with a bore scope and get a better look.

captjim

What exactly makes a cylinder head a "smog" head" The head alone does not determine, CR. Is it flow? Many old iron heads flow like crap, are they "smog" heads? I get that #8 heads came on mid 70's engines when emissions, unleaded gas, etc became a reality, but the fact is that it is a large chambered SBO head with larger ex valves, hardened seats, but needs a little work, especially on the Ex side. Even the "best flowing" old 350 heads could use some work.

devmar07

I checked the rear end code and I think it says 277 on the upper housing then a large A near the axle part of the housing

coppercutlass

if i remember right thats a 10 bolt. rear 8.5 ring gear you have some good choices.

devmar07

I also found a code near the bottom of the housing 1235197 but I have not seen this number or its placement on any websites for decoding and yes it is a 10 bolt

J-(Chicago)

I'd venture to say, that 8's and J's are "smog heads" You know, the ones that have no flow above .400 lift on the exhaust side.

captjim

Funny guy. Again, the reality is that NONE of these old heads were great on the hard ex turn.

devmar07

I suspect that I have 2.73 gears what do in need in terms of special tools and parts to change them to 3.42 and will there be a noticeable difference

coppercutlass

Big diffrence it will be very noticable.

captjim

You will probably be better off finding a complete axle. A ring and pinion swap is not easy nor is it a job for a novice. If you have to pay a mechanic it will be quite expensive. Also, you probably have an open rear.

devmar07

I built the entire car from any assembly manual I'm good at following directions but I will see what is out there. What's typically a fair price on and axle vs the price of regearing

captjim

Setting up a rear is as much art as it is science, it is hard to explain, but difficult to do correctly, IMHO.

devmar07

I will see if I can find someone then I can't seem to find an axle with the gearing I want and you are starting to convince me on not doing it myself

455man

I'll agree with captjim to have someone else do it. I've had friends do their own but it didnt work right when they were done. I got some gears and getting a posi today if all works out then having a pro put it in.

Find out what compression you have if possible before messing with the heads. Maybe put a shift kit in the tranny. Fiberlass OAI hood would lighten the load a little and give a little pep with the cold air.

HWYSTR455

I have to agree with this, especially to do one 'right'. There's a number of tricks and tips to make an 8.5 live under abuse or higher power levels, and I'm a firm believer of do it once, do it right.

I forget what the carrier spread is, but not sure you can use your existing carrier for 3.42s or 3.73s. Not much of a difference between the two ratios, and would recommend 3.42s over 3.73s.

After market axles, weld the tubes, check the housing to make sure it's true, housing ends, bearings, you're better off in the long run having a knowledgable person/shop do it.

.

devmar07

I'm body working a w-30 hood right now the only reason I was thinking heads was I've been told the 8s flow like crap but I would rather change gears and leave the engine alone after the suggestions on this post. The engine runs great and has great cruising power, just need some put you back in your seat action