416 running slower than expected

-
Header tube size too small for a 416 with ported heads with 2.02 1.60.
 
I'd go 17/8. You'll have to experiment with collector lengths to find the optimum.
 
I think that is a good run at 5300 ft above sea level for a full dressed street car. If you could hit a 10.90 at sea level, that would be a good run..... You cannot compare to somebody else's time run with good air
 
With a 416 at 800' elevation my 3050# fish (me in it) and 3.91, stock 'vert, SG, 275/60s would 60 1.68 but at the 660 it was doing 7.20 at 98+. The elevation may be hurting you but also the fuel line / pump/ gas pickup, etc may be what is hurting you at high power. You should have at least 3/8" lines from the pump to the reg, and I like a AN6 to the carb, one for each side - ie two lines from the reg to the carb.
 
I would just stick with a 1 3/4 header. Like the stepped TTI or dougs. Also nice to see someone from where my grandpa is from!
 
318willrun said:
I think that is a good run at 5300 ft above sea level for a full dressed street car. If you could hit a 10.90 at sea level, that would be a good run..... You cannot compare to somebody else's time run with good air
Click to expand...



x2. My first thought after hearing the altitude was "what's wrong"?
 
sounds like the suggestions are really good as to your problem. Just my 2 cents....Running pretty close to your combo, I have a little more lift than you and around the same duration. I am running 24 initial, 34 total with 10.6 compression, thing loves timing! Same heads fully ported, air gap, but running 1 7/8 primaries. I have read countless posts on the air gap to single planes and not much difference in times for the combo you have. That density altitude is a really killer. My car weighs about 3100 with me. I have been told it should be in the very high tens, but never proved it out.
 
Having lived in Denver (5800') for most of my life, I can tell you altitude is a power KILLER. The density altitude in Denver in the summer goes up over 9500' often (like when it is 90+ degrees out). My car picked up over a second when I moved to Indiana (850'). Your ET is a little soft compared to the 60', I would get a fuel gauge and check to see if you are loosing fuel pressure down track. I bet with some tuning you can get into the high 11's, but that is about where that car should be for the altitude.

For what its worth, my motor is very similar (410, ported Edelbrocks, 750dp) but with a smaller cam and it runs mid 10's...in Denver it would probably be in the mid to high 11's, but I have not run this current engine in Denver.

My old combo in Denver was a mild 360 (un-ported Edelbrocks, MP 509 cam), it ran about 13.8 on the motor and 11.1 on a 180 shot of nitrous. When I moved to Indiana that same motor first pass went 12.4 (picked up 1.4 seconds)...but I never did get to try the nitrous in Indiana before the engine died. My point is, at high altitude tracks, if you want to go fast you will either need to force feed the engine (blower/turbo), spray it with nitrous, or build a high compression motor. I liked having my own "atmosphere in a bottle"....If you know what your're doing, you can run real consistent and fast with nitrous...it just gets kinda pricey refilling the bottles.
 
You must log in or register to reply here.
-

Back
Top