I was also looking at your setup. I notice you have a 750cfm vacuum secondary. Are you sure the secondaries are opening? What spring do you have in it?

Ah, the fun of tuning. Check over your timing, jets, power valve, vacuum secondary spring...

Just curious, how did you get 10.6:1 compression?

 

but those 6300 lb crewcab cans haul lots of bootie down the track..... i got mine rolling on 38.5 " boggers with 4.10 gears, dana 60's front and rear and am turning low 15's in the 1/4....

 

Fomoco, I think you will be in the 13's. My old 390 with a rv cam ran mid 14's in my '66 f100. If you remeber I use to run that same cam you had but had ported cast heads. I raced a friend of mine that ran in the low 13's and stayed less than car lenght behind him. Getting closer to having my 418 built. just waiting on getting my rotating assembly back from being balanced!!

 

i also got 10.57:1 compression using flattop pistons then milled the heads.. did some mild polishing in the chamber and then opened up the close wall next to the exhaust valve to unshroud it and the cc'ed it.. just used standard flat top TRW's for the piston though..

 

i don't know how good you are in the fabrication department but a cheap hookup trick i came upon for my mud drag truck is a set of 90/10 drag shocks mounted up as kickers on the rear axle.. they have tremendous holding ability and stop almost all the axle wrap i was having at the drags.. made my peg leg diff work almost as good as a posi unit.... another cheap trick is take out your spiders and side gears in your open carrier and get a new set of thrust washers that shim in behind them... mix and match the new ones and the old ones until you have to use a hammer and brass punch to get it back together.. viola'!! instant posi on flat and level surfaces. the gears are so tight it won't pegleg on ya.. change your gear oil often though for a while cuz the shims wear and put out some fine metal powder..

 

I need to get the info updated, but keep in mind when looking through that stuff that the old TC has been upgraded to a TCI Streetfighter and it now has 3.89 gears. Just FWIW.

And a lot of folks have told me that the cam is too big. It's just taken until now to get all the major components in place and get this thing running good enough to figure out what's what. And if a cam swap is what it ends up needing to make it go faster, I'd definitely be open to that... 14's would be nice. 13's would be nicer!! Where's Rat been anyway?


Rusty - Funny you mention that... I really DON'T think the secondaries are working. Put a smaller spring in it, tore the diaphragm, got another one... still don't think it's working. Can't feel it "open up"... so that's probably a major culprit. 10.6 was arrived at by using flat tops and milling the heads. He sounded like he knew what he was talking about so I let him go for it.


Pol - You're the one I think about when the size of my cam is mentioned!!
13's would tickle the snot out of me, but seems a whole world away right now. Tweak this and tune that... Well, at least MAYBE now it's down to just tuning...

-Yeah, what he said!

 

13s are friggin' fast and down-right elusive for most of us F Series guys.

I think the only guy in the forum to actually get there is Freightrain with a dual quad 428 1/2 ton short-bed setup.

I might get there tomorrow night, provided things cooperate. I was just under 14.2 on street tires with a race weight of around 4700lbs, (F250 with a passenger)



Anyway, I don't think your times are all that bad. Keep tuning!

greg

 

i ran 14.10 with that 390 in my 72 f250 4x4. locked in the hubs to hook up and away i went!! truck was 4620 without a driver. never ran it after i did some more carb work though.. ex-wife got it in the divorce- OUCH!!! lmao

 

You're right, Greg... got to really go some to get these heavy old trucks into numbers like that... But hey, gotta have SOMETHING to wish for, huh!

YOU should get there... your truck belongs in a 13 second club if any of em do!

Raceboy- 14.10 is pretty dadgum good for a heavy 4x4 f250. I reckon that's what TRACTION will do for ya!

Dang those ex-wives!!

 

maybe it's the beer in me... But,I want to see a time-slip.

 

I think thats amazing! what's the setup for this 14.1 truck? .

 

Greg, you make me LMAO!! Ha ha!!

I may be the sucker, but FWIW, I believe it... Ya have to remember that leaving the line in 4wd definitely changes the game a bit. JMO.

 

I understand. BUt for what you gain at the line, you lose in the back end in power loss and weight. I also don't see how a 4x4 can weigh the same as my 2wd.

 

i got 5200lbs in my f150 4x4 with me in it. I cost myself 3 tenths alone.

 

5200??? Dang, that sounds heavy!! I need to find some scales and just see what my SB 2wd weighs, cause I don't have a clue...