Hot Rod Forum banner
1 - 16 of 16 Posts

·
Registered
Joined
·
139 Posts
Discussion Starter · #1 ·
I ordered my 3.73s for the 66 today. So I am going to run those with the current set up and then see if that cures the launch bog and if I get an improvement in my quarter E.T. With my current set up what do you guys think would be my best next future change. Keeping in mind I am not looking for a super fast street car. I am looking to hopefully get the car into the 12s. 12.99 counts!!
My present setup for those who have not seen it posted. Motor is a 355 with Trick flow aluminum heads, 180cc intake port, 64cc chambers and 2.02/1.60 valves. Present springs have an installed pressure of 94-96lbs and an open pressure of 480 lift =288lbs. I give the spring info for cam upgrade limits. Cam now has a .454 @.050 lift and .216 @ .050 duration. 1.5 stock stamped rockers and hydraulic lifters. Pistons are dished at either 12 or 15.7 not sure as the info I got from summit lists both. Intake is a Edelbrock Performer and carb is a 1406 Edelbrock 600 cfm. Headers are Terminators by Flow Tech and I believe are 1 & 5/8 inch. 2 & 1/2 inch exhaust with H pipe. 4 Speed Manual T-10 Richmond Transmission. My present best is 13.87 @ 100.65.
 

·
Registered
Joined
·
17,613 Posts
I'm figuring your static c.r. at about 9.07:1 using the 12 cc dish figure and 6 cc's worth of piston deck. If that's the case for sure, then you're all done on the cam until you rebuild for more c.r.

What's your 60' time? Could you stand some improvements on launch? It looks to me that 100 mph should be a little quicker than 13.87, so maybe there's some improvement to be made there. What tires? What rear suspension?
 

·
Registered
Joined
·
139 Posts
Discussion Starter · #4 ·
My deck height is .001 or -.001 according to build sheet. what does that do to your CR numbers? My 60ft times are pretty bad 2.20s. I have to spin at the line to keep the revs up. If I dead hook I get terrible bog and the 60ft. times are just as bad. Runing Drag Radials on the rear and suspension is pretty stock. Just put poly graphite bushings in everything, lowered the front 1 inch and put new shocks (not drag shocks) on and boxed the lower rear control arms with an air bag on the passanger rear.
 

·
Registered
Joined
·
17,613 Posts
O.K., at the risk of gettin' sniped, I'll tell you what's on my mind. First, I don't see anything wrong with the cam in the motor now. It makes power to 5,200. With a 3.73 gear and 88" tire, 5,200 comes up at 116 mph. You're not even close to 116 yet, so don't swap this cam for one that will make power further up in the range and kill off the bottom end where you need it right now.

I grew up in the mid-late 50's and early 60's. Most everything on the streets was a 3 or 4-spd car and most of them powered by small block Chevies. We had the same problem you're having now, heavy car, little motor.

You are aware I'm sure that you will never be able to optimize the car for either street or drags by trying to address both venues with the same platform, so either be thankful that you have a 13 second car and be happy with it or move more toward the drag side and away from street happiness.

Assuming you have the pump shot optimized for volume and duration and that it is not a lean bog you are experiencing, we'll have to contend with the awful truth. You need more gear. A 3.73 ain't gonna cut it. With the 4-spd cars we ran way back when, we had to use 4.11's or better to launch. Most of the guys with the '57 Chevies were runnin' 4.44's or 4.56's because their first gear was a 2.20 ratio. I think yours is a 2.43, so you're not much better off.

The other thing we used to do for strictly strip cars was to use a very heavy flywheel to keep the rotational inertia up when we dropped the hammer. I don't know how practical a 50 lb. flywheel would be for a street car, but I'm just throwing it out for you to consider.

If I were faced with your dilemma, I might be thinking about replacing the T10 with a T5 upgrade from g-force transmissions. With a 2.94 first gear and your 3.73 rear, you'd be at 10.96:1 for a final drive first gear ratio, as opposed to 9.06:1 with the T10. With a .59 5th gear, final drive in high would be 2.20:1. I'd opt for the helical cut gears to reduce noise a little.
http://www.gforcetransmissions.com/tran_gt-5.asp
 

·
Registered
Joined
·
4,104 Posts
about one minute into your first test drive after swapping out the 3.08's......

you will be saying: WOW WHAT A DIFFERENCE!!!!....

12.99/3400 lb car = 300rwhp (360fwhp).....your darn close to that

???? air bag on the pass side.....with a 3.73 open rear you will need more load (batt in the trunk?) on that side.....the bag helped you "spin" with the 3.08's and cost you alot in 60' and ET
 

·
Registered
Joined
·
4,104 Posts
http://www.jason.fletcher.net/tech/freetips/freetips.htm

oregon,
here's a link from the knowledge base to some (of the 150+?) "tweeks" to improve ET at the strip....it really is as much about "tuning the car" for ET as tuning the motor for HP

can be 3 tenths quicker "tweeked" once you have found most of them

(plugged in the basics of your motor into my DTD, 12.99/3400lbs=360fwhp, DTD says you are at 350fwhp and 380ft/lbs, yup, you are "darn close")

poncho,
that was the only "prep" article I found.....did I miss some?
 

·
Registered
Joined
·
139 Posts
Discussion Starter · #12 ·
With the 3.08s I dump at 4000-4500. Any less and it bogs. It spins at this rpm but the revs stay up so I ET better. 60 ft. is about the same as if it were to dead hook and bog, ET is at least four tenths better though.
 

·
Registered
Joined
·
139 Posts
Discussion Starter · #14 ·
when it dead hooks and bogs the rpms drop pretty low. I would say about 1000. Not sure as I have not looked at the rpms during the bog. Test drove with the 3.73s and it goes through the rpms much quicker now. I do like these gears better. Now I hope my ET will drop as well.
 

·
Registered
Joined
·
69 Posts
cool! It should be much better. I just ordered an eaton posi, richmond 3.73:1 gears with install kit, a reinforced cover and a stud kit for for my 10 bolt. Right now I just lose traction...no wheel hop, no bog, just NO traction from my 3.08 open diff with 255/50zr18's.
 
1 - 16 of 16 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top