[4dblnkldude]

I've been trying to get my 69 firebird into the 11's for a few years now. First pass off the trailer yesterday the car does an 11.76 at 119 mph!!! I usually launch the car at about 3000 rpm, this time I came outta the hole at 1800 or so. The car actually hooked and booked down the track. It was a really good run and I figured it at least had to be as good as my previous best of a 12.04. When I got the time slip I could not believe it.

[prostreet64]

Congratulations! That is a great feeling when that time slip is a new best. What is your combo?

[4dblnkldude]

It is a 455 .030 over, e heads slightly ported, xe-284 cam, 1.65 HS rockers, edelbrock torker with water crossover separated, 850 4150, dougs headers, TKO-600, ford 9" with 3.89:1 gears, cal tracs, cal trac split monos. The 10 bolt nodular rear got eaten by this combo. I know it can get faster with an auto. I could also put some wider tires on it but this is a street car, will never be tubbed, or have a cage in it.

[scott70]

Nice!! 119 shows enough hp to go a couple more tenths quicker but would have to be a hard launch considering the manual trans.

[grandam1979]

That is a really good mph for a 11.70 your making some good hp. Congrats on the new best.

[grandam1979]

What tires are you running?

[4dblnkldude]

M&H racemaster dot street slicks. 245/45/17. I dont know if a 275 will fit in there. Funny thing is I know what I have to do to get it to hook better at higher rpm I just don't want to do it. I ordered a roller cam kit from butler last year to swap in to see if that would get me into the 11's..so now what do I do. I was gonna pull the engine the day after thanksgiving to swap it in among other things, I guess I still will, not like I can return it after over a year.

[prostreet64]

Man, that is a really good pass with a 5-speed. If you had an automatic and more cam I bet you would see low 11s at least. What was your 60' time?

[prostreet64]

Curtis runs the MT ET street drag radials, 275/60x15 and they fit nicely in the 69 wheel wells but the backspacing needs to be just right. Can't remember that measurement off the top of my head but I could look it up. What size roller cam did you get from Butler?

[4dblnkldude]

I only went a little bigger at 242/248/112 duration. The lift with 1.65's will be .619 and I think .591 on the intake. I think I'm going to advance the cam 2 degrees. I'm hoping the roller cam will smooth things out a little. I think my back spacing is 5 3/4". I had 18x10 on the back at one time.

[4dblnkldude]

Oh 60' was 1.72.

[OCMDGTO]

Awesome run congrats! What changes did you make to knock off 3/10s? Really impressive with a manual trans

[4dblnkldude]

I did drop the exhaust and take the air cleaner off. All of my other 12.0 runs were still at 117 or so.

[stags]

Congrats Matt - that's the way to "get into" the 11's alright. If only going fast didn't always lead to going faster this would be a lot easier haha. Not sure what I would do now but whatever you decide: good luck.

Happy Thanksgiving

[Lee]

Originally Posted by 4dblnkldude

I did drop the exhaust and take the air cleaner off. All of my other 12.0 runs were still at 117 or so.

If you drop the exhaust (which should lean out the AFR significantly) and gain that much power, then you are probably jetted too rich for when the exhaust is hooked up.

My cousin's T/A was way rich, and gained big e.t./mph when he opened his exhaust. One of my cars was jetted dead-on, and had horrible lean-stumble when I opened the exhaust on it. Something for you to maybe consider & test.

I ran 275/60-15 MT drag radials on my '67 Firebird. It would 60' as low as 1.53, running 24psi. I drove the same tires on the street, and never had an issue, never rubbed.

That same car ran 11.2's when I got the MPH to 119, so get ready to be told to get a rollbar! :-)

[4dblnkldude]

Originally Posted by Lee

If you drop the exhaust (which should lean out the AFR significantly) and gain that much power, then you are probably jetted too rich for when the exhaust is hooked up.

My cousin's T/A was way rich, and gained big e.t./mph when he opened his exhaust. One of my cars was jetted dead-on, and had horrible lean-stumble when I opened the exhaust on it. Something for you to maybe consider & test.

I ran 275/60-15 MT drag radials on my '67 Firebird. It would 60' as low as 1.53, running 24psi. I drove the same tires on the street, and never had an issue, never rubbed.

That same car ran 11.2's when I got the MPH to 119, so get ready to be told to get a rollbar! :-)

I actually thought about jetting up! I figured by dropping the exhaust I would gain a mph or two. So I decided not too jet up. Turns out I gained better knowledge by not doing it then. This car is my baby I've had it since I was 19, it will never have a cage in it. My son is 15 and he has got the car bug here in the last year or so. Depending on how things go I may take this engine out and put it in a 79 formula that I'll be getting here in the next couple weeks. Then it will be his time to race.

[grandam1979]

What is your exhaust? 2.5-3” over rearend?