Last month I posted the topic "Cylinder Pressures". Just thought I would update everyone on the end results of my modifications, as they ultimately turned out great!

Here is a rehash of what I did to my bone stock 1973 4-door Grand Am (62k miles) (400-4 motor. Performance before averaged 16.78 @ 86 MPH.

Heads swapped for 1971 #96 heads.
Intake swapped for 1971 cast iron unit.
Original Q-jet prepped by THE CARB SHOP.
Ignition upgraded to HEI.
Exhaust manifolds changed to cast iron Ram Air Headers.
Exahust upgraded to 2.5" mandrel bent, X-pipe & Walker 17749 mufflers.
Cam changed to COMP CAMS XE-262.
Rockers upgraded to Magnum 1.52 roller tipped.

The rest of the drivetrain was left alone. Stock torque converter in the turbo-400. Rear Gears are 3.23, no posi.

With the XE-262 cam, the motor was a dog off the line. I checked the cylinder pressures, which were 115-120 PSI. They seemed low, which I later found out were also being effected by the near 6000' elevation I live at.

None the less I was bent on changing the camshaft, so I purchased an engine simulator, PERFORMANCE TRENDS, and began to mess around with camshaft profiles. I ultimately came up with a profile much more mild. Oregon Cams ground up the following custom camshaft, Duration: 202/208 @.50, Lift: .413, .426, Seperation: 114 degrees.

What a diffence, the Oregon ground camshaft really woke my car up! It now pulls hard off idle and still pulls to 5000 RPM. I tested the car in the 1/4 mile again. With a passenger in the car (test weight 4513 lbs), it now runs 15.49 @ 94.5 MPH. This was at an elevation of 1200 feet. That computes to 353 gross H.P. (at 1200') or 367 H.P. at sea level. Not too bad with a low compression 400 motor(8.2 to 1) running on 89 octane gas!

Last month I posted the topic "Cylinder Pressures". Just thought I would update everyone on the end results of my modifications, as they ultimately turned out great!

Here is a rehash of what I did to my bone stock 1973 4-door Grand Am (62k miles) (400-4 motor. Performance before averaged 16.78 @ 86 MPH.

Heads swapped for 1971 #96 heads.
Intake swapped for 1971 cast iron unit.
Original Q-jet prepped by THE CARB SHOP.
Ignition upgraded to HEI.
Exhaust manifolds changed to cast iron Ram Air Headers.
Exahust upgraded to 2.5" mandrel bent, X-pipe & Walker 17749 mufflers.
Cam changed to COMP CAMS XE-262.
Rockers upgraded to Magnum 1.52 roller tipped.

The rest of the drivetrain was left alone. Stock torque converter in the turbo-400. Rear Gears are 3.23, no posi.

With the XE-262 cam, the motor was a dog off the line. I checked the cylinder pressures, which were 115-120 PSI. They seemed low, which I later found out were also being effected by the near 6000' elevation I live at.

None the less I was bent on changing the camshaft, so I purchased an engine simulator, PERFORMANCE TRENDS, and began to mess around with camshaft profiles. I ultimately came up with a profile much more mild. Oregon Cams ground up the following custom camshaft, Duration: 202/208 @.50, Lift: .413, .426, Seperation: 114 degrees.

What a diffence, the Oregon ground camshaft really woke my car up! It now pulls hard off idle and still pulls to 5000 RPM. I tested the car in the 1/4 mile again. With a passenger in the car (test weight 4513 lbs), it now runs 15.49 @ 94.5 MPH. This was at an elevation of 1200 feet. That computes to 353 gross H.P. (at 1200') or 367 H.P. at sea level. Not too bad with a low compression 400 motor(8.2 to 1) running on 89 octane gas!

wk,
Where do you live? Just wondering because of the altitude of 6000'

Just curious...was the 16.78 @ 86 MPH run at 1200' also? If not, that'll skew your numbers.

If so, nice job!

I live in the San Bernardino Mountains (Southern California). The city of San Bernardino is about 14 miles away at an elevation of 1200 feet. All my tests were done in San Bernardino. It is a hell of a climb up the mountain and will really test your cooling system!

202/208 -- did you install it straight up or advance cam?
 

hi -- i also went for a mild cam, the isky intake 202/208 @ .050 .425/435 exh at 112 lsa on my 65 389 tripower, .030 over and a SCR of 8.7:1 for daily driving on 87 octane. Nice cam but so far, it's solid but won't even spin/chirp the tires off line, even with a 700R4 and 3.55 posi. I'm playing around with timing but am somewhat stuck. My stock 350 lemans and a 3.08 spins/chirps with turbo 350.

My next plan is to look the center carb, it's likely overjetted now at .64

Sorry to be the bearer of bad news, but this thread is almost 4 years old and the original poster hasn't posted to the forum since June of '05. I would start a new thread and ask your question. You'll be much more likely to get a response from some one.