My car has been together for a while now, but after reading some of your views on header size, I'm starting to second guess my choice. Could some of you look over my combination and give me your opinion on my primaries. I have no idea how much HP I have. (maybe some guesses there too) I'm mainly wondering if I might be able to help my 60' with a change to 1 3/4.

468 CI
Edelbrock RPM heads (110)
Airgap intake
2465 TRWs (10.43:1 comp)
Crane solid flat 238/248--544/567
Pro Sys HP950
HEI w/ MSD6AL
Harland Sharp 1.7 rockers
Moroso stud girdle
Carter 172GPH pump
400TH trans w/ 2800 conv.
4.10 gears
Hooker Comp 2" pr, 3 1/2 collectors
Pypes 3" system w/ X-pipe
Car is 3800lb without driver

The car is raced with exhaust system up. If I had it to do over, I would probably get the 1 3/4, but don't know if it would be worth the money to change. Thanks for any opinions.

Danny

Funny, thats one of the only cam's I know where OPENING up lash might give you a better ET. Very slow ramps on that one, opening lash gives better accelration off the seats. CAVEAT: It did nothing for Barista. Seems to me that most that have done the header swap dont get much, if anything. I'd try lash at .024->.025 first and see if it bumps the short time. . Plus, your X crossover increases velocity flow through by using the scavenging of pulses. I bet you see nothing by a tube swap. 3500 stall efficient converter is a better bet.

Thanks, L88. Thats good info. Not knowing, I recently moved the lash closer to 20-21 trying to get a little more lift. Was looking for some MPH help. I should have known that wasn't going to help the bottom any. Would that 3500 be fairly drivable on the street? Thanks.

it'll be fine if you don't mind getting 7 MPG. but with 4.11s you're probably already used to the mileage deal.

Tom, you're pretty close on that gas milage estimate as it is. It's not exactly what the federal government had in mind, but I didn't build it for nor am I real concerned with fuel economy. More worried about point A to point B which would be 60 feet away. Thanks.

Danny

Tom, you're pretty close on that gas milage estimate as it is. It's not exactly what the federal government had in mind, but I didn't build it for nor am I real concerned with fuel economy. More worried about point A to point B which would be 60 feet away. Thanks.

Danny

You're only getting 7 mpg with that engine. Heck, I was getting 8 mpg out of my last engine with the car running mid 10s. 5 on the highway and 3 around town :D

Seriously, on your headers... Have you ever uncorked them at the track, and if so did it slow the car down? If anything, I think it might benefit from a smaller collector. A set of merge collectors could show an improvement and would be a lot cheaper than a new set of headers. However, I suspect they might be difficult if not impossible to install with the X-pipe already in place. If possible try disconnecting (not removing) the exhaust and run the car back to back at the track. This might be tough to do with the x-pipe. With regular dual exhaust I could unbolt the collectors and move the exhaust off to the side and secure it to the outside of the collector flange with one bolt. My expectation based on my own experience is that the car will likely slow down. If so, then you might see an improvement from a smaller header with a smaller collector.

[QUOTE=kjett;1213344]You're only getting 7 mpg with that engine. Heck, I was getting 8 mpg out of my last engine with the car running mid 10s. 5 on the highway and 3 around town :D

Kjett, all that means is I wouldn't want to race you on the dragstrip or crosscountry.
I've tried open exhaust, but it was different tires, carb etc. It's not a problem to drop. I had an extra set of collectors install in front of the mufflers so I can easily drop the X out. But I really don't think my car is any faster opened up. Maybe, like you suggested, not as quick. Thanks.

Danny

[QUOTE=kjett;1213344]You're only getting 7 mpg with that engine. Heck, I was getting 8 mpg out of my last engine with the car running mid 10s. 5 on the highway and 3 around town :D

Kjett, all that means is I wouldn't want to race you on the dragstrip or crosscountry.
I've tried open exhaust, but it was different tires, carb etc. It's not a problem to drop. I had an extra set of collectors install in front of the mufflers so I can easily drop the X out. But I really don't think my car is any faster opened up. Maybe, like you suggested, not as quick. Thanks.

Danny

Danny, I would definitely try it back to back if it's any easy thing to do. If you "drop" the x-pipe, be sure to factor the weight difference into any performance differences you measure. BTW, my comment about fuel mileage was a poor attempt at a joke... 5 on the highway and 3 around town equals 8 :) My next engine will be something more hightech and fuel friendly like a power adder LS1 :) Good luck and keep us posted :thumbsup: