jpdog357

Guys:

Love the forum and know this is a great place to get some advice.

I have a '72 Lemans, 400 2 bbl. Body, interior, etc. is rock solid and great but the factory 2bbl low hp 72 400 needs to be woken up a bit. Just for street driving from corner store to 150 mile trips.

For the time being I am on a pretty tight budget so I am thinking carb, intake and maybe headers. Not sure if I will go as far as cam and heads are financialy out of the question.

Can I get some advice on some options that would work with stock heads and cam? I think the flow on these engines is pretty low and don't want to over carborate.

Thanks,

Jason

 

05GTO

In my opinion,
go with an Edelbrock 2156 intake manifold and use one of Edelbrocks Thunder Series AVS or Performer Series Carburetors. I don't think you will see much of a difference with headers unless you change the cam, heads and increase the compression ratio.

__________________
Randy

jpdog357

What are your thoughts in regards to CFM?

Jason

BobG

If you've got a 400, and your redline is 5K, you should be more than good with 650 cfm, unless you're going forced induction

There's a web calculator somewhere on the internet that has gobs of useful info, such as how to calculate max cfm for your motor, what gear to change in your speedo to correct for over/undersized tires, etc... I forget the site, but do a web search for' "carburetor" and "cfm" and "displacement" '

my 2 cents

Ragtop70

Due to parts interchangabilty the low comp 400 can be woke up fairly cheaply. Look for used factory parts at swapmeets or the salvage yard.

If you're on a tight budget look for a ponitac 4v intake at a swap meet. For your heads a '72 would be ideal. A 73-74 will also work. Avoid 75 and later as they have smaller secondary venturies. 68-71 manifolds will work but you will need to block the heat riser at the head. Expect to pay 20-50 bucks at a swap meet. As a rule of thumb the later models are cheaper. Often you can score one with a re-buildable quadrajet thrown in.

An easy valve train upgrade is to swap out the stock rocker arms for a set of 1.65 ratio rockers. To save $$$, by pass the fancy roller tiped or full roller type. Just get a cheap set stock type- I think mellings makes a set.

For a few more bucks and more work look for a good set of heads. Best bet 67-70 with 2.11 intake and 1.77 exhaust valves and screw in rocker studs. There are lots of casting numbers but "670", 12, 13, 16, 62, 48 are all good. Expect to pay $100-400 for a pair of workable heads.

My college roomate had a 77 T/A with the original 400, #62 heads, '68 intake, quadrajet carb, HEI dist, 068 cam, and 3-tube headers, and full duals. With the stock turbo350 and 3.08 gears it ran consistant 14.0's at 100 on skinny radials. Best was 13.90 @ 101 on a cool night. It was a cheap build-up.

jpdog357

Thanks for all the great feedback!

I really appreciate it. I am clearly not all that mechanical and your advice is very valuable.

I will probably go with an edelbrock setup and keep it all simple for now as far as heads, cam, valves, etc.

I will however, be looking for a limited slip rear end as my right side is getting more of a workout than I need.

Thanks again,

Jason