I shift at around 6700 RPM's, car seems to get the best times around there.

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'69 Mustang Fastback, 351C, Holley 950 HP, New Parker Funnelweb,4-v quench heads ported, 10.75:1, UD pulley, windage tray, Top Loader, 3.89 9" rear

And your right I am using street tires and I obviously can't launch or drive this thing for sh** yet. I'm considering getting some ET streets.

I was looking at 4.11 gears and that would have me crossing around 6300 RPM's. 4.33's would have me crossing around 6600+ RPM's.
Which are better for the application in your opinions. I shift around 6700 RPM's but I suspect my peak power tob 6300-6600 RPM's (no dyno time yet).

With the other specs. you list, if its a solid and you have oil restrictors, turn er up. 4V heads like RPM. With a properly prepped motor even with stock rods with good bolts, 7000 is not too high. KV has run stock rods with good bolts all along and believe me, they have seen 7500 + many times. The only times a rod has failed was when a bearing spun.

If its equipped with a hydraulic cam, then 6800 or so is enough. Without oil restictors, all the oil wants to end up in the top of the motor at high RPM. If a 4.30 gear gets you about 6700 or 6800 in the traps, then that's what I'd do.

It is a small cam however, so it might peak at 6000 RPM's, but it doesn't act or feel that way. I'm comfortable running it to 7000 RPM's because I do have the oil restrictors in place, ARP hardware, and the assembly was dynamically balanced. I do think that I'll pick up a couple MPH with the gears and slicks too, so around 118 MPH at the line.

I guess I'm hearing 4.33's are the way to go. Just seems like a lot for running around on the street. Let me know your opinions.

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'69 Mustang Fastback, 351C, Holley 950 HP, New Parker Funnelweb,4-v quench heads ported, 10.75:1, UD pulley, windage tray, Top Loader, 3.89 9" rear
-------------------------12.51 1/4 mile @ 115.89
60 foot 2.008 (ouch)

[This message has been edited by '69Stang (edited 11-12-2002).]

Once you do get it to hook-up, you'll find out where your next weak point is. A stock 9" carrier will spit out the pinion gear sooner or later.

Seems to me like you are real close to having a race only car. You can probably gain in E.T. by improving 60' times while all the time making the car less streetable. At some point the chassis will start flexing making more mods a necessity, like frame ties and/or a roll cage.

If you have a nice 69, I'd think pretty hard about doing much more to make it faster on the track, if it were mine. We came to the same point years ago with KVs 70. We got into the 12s in street trim with slicks and open exhaust. The car was too nice to cut up and we started looking for a better candidate to make a racecar out of. 69 and 70 fastbacks are the ultimate bad-a$$ looking street cars to my way of thinking. If I had a nice one, I'd make it a streetable hot rod, as it were, and find something else to race.

Speaking from experiance, you wont see much gain, if any, if you go to a 4.11 gear. It will take more of a change to gain much et. I would suspect 4.33's, or even 4.56's would be best. But, then your street car becomes not so "street friendly". I used 4.71's in my street car awhile, that and a 4500 rpm convertor. It was fun to drive, so long as I didnt want to go very far. I would get the 4.33's, and some real slicks, and have fun with what you got.

I'd think a set of Moser axles would be a good investment also. A 4 speed car has no "give" in the drivetrain like an auto trans does. If it hooks up hard, something is more likely to break.

These things do tend to get out of hand also. Several years ago some guys showed up at Eddyville for a quick 16 race, I think. They had the baddest, nastiest, in your face means business lookin 69 fastback I've ever seen. It had a super neat red paint job on it and a monster big block, as I recall. KV might remember better, but I sure remember the car. It may have had a Lenco in it, now that I think about it.

I talked to the guy quite a while and he said the thing started out as a street driven hot rod, basically, and went way wrong at some point. By then it had the steel roof clip left from the original car and that was about it.

Anyway, my point is that if you want to keep your car fairly streetable, you might not want to do too much more. It sounds like you have a cool streeter that is fun to take out and play with. I'd love to have one like that. The 69 fastback is my favorite Stang.

Personally, if that car was mine and I could afford it, I'd put a milder motor in it for the street and build a full blown racecar for your roller motor (with a bigger cam). You've got a really good start on the motor.

He did say it started off as a fast street car, the progressed to a 10.90 super street car and somewhere along the way got out of hand.