john mann

Hello, thinking of doing a upgrade to our 67 442 car, right now we have a chevy 331 12 bolt posi in it, were thinking of going to 355 or even 373 the car seems to need a little better gear, we are in the country in only gets out like 4 times a year and we like to bring it to rock falls and run the car on the track we don't care if she tacks up cuz like i said we don't really go anywhere with it, ill try here to list as much info as i can to see if any body has some suggestions on a good gear for it, we have a 455 +40 in our 67 442 right around 1000 miles on it, jm 18-20 cam 260/268 488/496 Ka iron heads coan converter 2800 stall turbo 400 trans with shift kit, L69 3x2 we have 65 jets in the center and 70 jets on the ends, w/z manifolds, with cut outs, best run closed all the way to the back 13.64 at 99 mph, we have not opened it up yet... any suggestions would be much appreciated, thanks john.....

wr1970

I would go for a 373.

rtanner

john, what size rear wheel and tire? what is your current 60ft?

john mann

just out here in the country b/f Goodrich 215/70/14 27" dia, i have these hooiser slicks i use at the track there 10"x26" at the track my best 60' time was 1.976 usually around 2.000 to 2.100 hope this helps you !! john...

wr1970

Yeah like whole gear change. That tire size with a 373 would be like using 390 rear gear. Like i said before 373 you will get rpms. If you want to slow it down on rpms just go taller. 28/29

john mann

the motor seems to be all in at about 5300 to 5400 will i see the end of the quarter mile running the 373 with my 26" tall tires in that rpm range. i tried using the rpm calculator it had me at like 5200 plus wont i have a little converter slippage that would even bump it another 100 to 200 rpm? thanks john..

wr1970

Might be at 5500/ 5600 better try cut out then closed.Don't worry about the converter. You are going to be in the twelves my guess 12.70's to12.8's . Depends on 60 foot and chassis.Let the 67 run just don't go over 6000 rpm.

john mann

IAM thinking if its wringing out like that, i should go then to a 27" tall slick like you said to knock her down on the reves a little, i have once over would it there, i looked over at the other car next thing i know i saw 5700 with stock rockers, they didn't float though (valves) i wont do that again !! i think that the 373 are whats best for this particular car, i just want to make sure i don't have to shut her down before the end of the quarter, thanks for all your info !! john !!!

GEARMAN69

That ET will require more HP than a 99 mph trap speed of before though. At least 105-106 generally. The 3.73 gear is perfect though, allows you to fine tune with tire diameter

wr1970

99 mph trap speed was closed exhaust. That is why i said run it open with the 373 then close it to see if mph is better closed.The stock exhaust manifold is restrictive to flow. All i am saying is gear, cam, engine ci makes it possible. Will he attain 12.70's 12.80's Depends on his suspension, weight, and if chassis is set up to race stock shocks suck. Set of headers would help. A lot of factors but i think do able.

GEARMAN69

It will pick up with it open just interested to see how much

wr1970

John report back when you get a rear end under the car please. Also think about other upgrades.

john mann

fore sure, as of know iam trying to either find a 373 compete diff, or and this is the way it will probably go. just have mine gone thru i will need to find somebody real good here in Minnesota to do the set up on the diff !! thanks again to all for your info !! john.....

john mann

ok, i left for now the 331 in it, just one thing at a time, all we were looking for with the car was 13.50 flat, so we went to rock falls and uncorked it, we had the end carbs that were bought from the parts place opened up from 1 3/16 to the correct 1 5/16 that's all we did no tune up in 6 years, my bad, still ran it, first run 13.69 98.00 second run 13.71 98.20 third run 13.55 98.89 fourth run 13.51 98,75 fifth run 13,42 99.26 sixth run 13.43 99.36 we are going back there oct 1 with a fresh tune up uncorked, iam fine with the et, just want to hit the century mark !!!!

wr1970

Cool i am glad you tuned it up now you know you where you are at. If you want to up grade then you know where to start on components. Please report back after you run it in October.

olds 307 and 403

Those 2 second 60 ft suck, my slow 350 runs a 2.+++ to a 2.1 60 ft. I am stepping up to 3.90 gear when it goes in the 70 S with OD and more cam. Your cam is small for a 455, what is your compression?

john mann

this time all my 60 foot times were 1..990 to 1.885 i thought this was pretty good for what it is !!