FAQ |
Members List |
Social Groups |
Calendar |
Search |
Today's Posts |
#1
|
|||
|
|||
Well, you guys talked me out of it
The 2802 cam that is. With the 093 head and press in studs I have decided the best course of action is to change the cam to an 068 or something similar. I do need some good vacuum for the A/C and brakes as well. Another concern I have is the compression. I may run into detonation problems so is there a cam spec I should be looking for that would help mitigate pinging? Also, I bought a Hughes 2500 stall converter to use with the 2802...I can still use it with the smaller cam can't I? Have 3.08 gear now but am getting a 3.55 in future to use with a 200-4R.
__________________
Resto almost done - 1966 GTO HDTP Tiger Gold (paint code 1-2), black vinyl top and interior, 389 tripower, 068 cam, TH-350/Hughes TC, RA manifolds, 2.5" Pypes exhaust, Scarebird Front Disc, Ralley II's, factory PS, PB, PW, PA, A/C, headrest option. |
#2
|
||||
|
||||
Stay away from narrow LSAs (110 or less) to reduce pinging and provide good vaccum. The 068 might actually be too wide an LSA for your current gear though (you lose a bit of torque). Another thing I don't like with the 068 is the ultra conservative lift. If you go that route use 1.72 ratio rockers for sure.
but I think your best bet would be a Summit 2801 or similar (112-113 LSA, 212-215° intake, add another 6-10° exhaust, and as much lift as possible).
__________________
"The Mustang's front end is problematic... get yourself a Firebird." - Red Forman |
#3
|
|||
|
|||
DBiggs
In helping to mitigate ping the wider LSA helps since it in effect positions the intake valve so that it closes later. Amc Mike You mentioned a 112-113 LSA. Other then the 068 I have not seen a catalog cam that is greater then 112 LSA in the range you recommended. Do you know of one? |
#4
|
||||
|
||||
The Hughes 2500 converter will work fine with the 068 cam, a mild converter upgrade works well even with a stock cam. It should also help to keep the pinging down since it won't load the engine quite as much right off idle.
I would run stock 1.5:1 rockers with the stock press-in studs. The higher ratio rockers may stress the weak stock studs too much. Even the stock screw-in bottleneck studs should be replaced with straight 7/16" screw-in studs (big-block Chevy type) when running 1.6:1 or higher rocker ratios.
__________________
1964 Tempest Coupe LS3/4L70E/3.42 1964 Le Mans Convertible 421 HO/TH350/2.56 2002 WS6 Convertible LS1/4L60E/3.23 |
#5
|
||||
|
||||
112lsa)
__________________
https://www.flickr.com/photos/197745168@N07/ "There's nothing more unsatisfying than watching an electric car go down the dragstrip." |
#6
|
||||
|
||||
The 2802 will work great with the compression that you have. I run a 400 with #16s and use the Crane commander version of the 2802 cam. I run pump gas and 3:73s which I just went with taller tires and its fry tire time even at 20 miles an hour with MT drag radials.
0-60 ft in 1.67 seconds and 1/4 mile time in 12.5 seconds. No detonation, power brakes, and run cool at 165-175 sitting in traffic. I havent even worked on trying to tune it better. Also Im running non ported heads. 2802 would work fine, especially with the 3:55s and 2500 stall and the low first gear of the 200-4r. With the 114 deg lobe separation, it will give you a very broad torque band and give good vacume. |
#7
|
|||
|
|||
Quote:
__________________
Resto almost done - 1966 GTO HDTP Tiger Gold (paint code 1-2), black vinyl top and interior, 389 tripower, 068 cam, TH-350/Hughes TC, RA manifolds, 2.5" Pypes exhaust, Scarebird Front Disc, Ralley II's, factory PS, PB, PW, PA, A/C, headrest option. |
#8
|
||||
|
||||
You could pull the heads, get some port work done and the screw-in studs, leave the short block and compression alone and go w/an XE or maybe Voodoo cam in the 225 @ 50 range. That baby would SCREAM in first gear w/3.55's and a 200r-4.
|
#9
|
|||
|
|||
Quote:
what kind of vacuum are you getting with the 2802? I won't be racing this car, its just going to be a weekend cruiser. Would like as much vacuum as I can get for the PB and A/C. When I picked the 2802 I just looked at the duration at 0.050...which seemed pretty tame. I have no feel for how this cam will act...never had such a slow ramping cam before. Only when I noticed the advertised duration did I become concerned that I bought too big a cam. That and the revelation that I needed to use screw-in studs for that cam. As you can tell I'm a bit new to Pontiacs.
__________________
Resto almost done - 1966 GTO HDTP Tiger Gold (paint code 1-2), black vinyl top and interior, 389 tripower, 068 cam, TH-350/Hughes TC, RA manifolds, 2.5" Pypes exhaust, Scarebird Front Disc, Ralley II's, factory PS, PB, PW, PA, A/C, headrest option. |
#10
|
||||
|
||||
Right cam / Pontiac Gregg
The Summit cam is not that great, mass produced $ 32.00 ( my cost )cam.
The 068 is Ancient tech. Want a GOOD cam ? Get AN Ultra-Dyne !! For your application, I'd recommend a 272/276H12+6, degree it in @ 104. @ .050 217/221, lift: .454/.454, won't snap off those press in studs Worth 30 horse over either of those other 2 cams, and it will work with the 3:08's. Not recommended though. With the 3:08's or 3:55's in over drive, it wil slow down the motor too much. Since you have over drive, I'd stick in a set of 4:11's in the rear. With the overdrive, you're looking at approx. 3.20's with 4:11's . I've done the taller gears and the car will actually get BETTER mileage cause the motor is in a more efficient rpm range. Call if you want the right type of cam. I run you through all the details. Ask all the questions you like, hey, it's just a phone call ! 1-303-776-0877 Pontiac Gregg
__________________
Greg Merrick |
#11
|
|||
|
|||
Quote:
I have a feel for the modern cams and how they act...had a cam in a 383 '70 Road Runner that was 223/230 .503/.514 and it was what I consider a mild cam. It had an adv duration of 272/280 I believe. I would think this Ultradyne would be even milder in a 389 +0.060 over and less duration.
__________________
Resto almost done - 1966 GTO HDTP Tiger Gold (paint code 1-2), black vinyl top and interior, 389 tripower, 068 cam, TH-350/Hughes TC, RA manifolds, 2.5" Pypes exhaust, Scarebird Front Disc, Ralley II's, factory PS, PB, PW, PA, A/C, headrest option. |
Reply |
|
|