Thread: What do you guys think of this combo for torque...

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Okay. I did take into consideration what you guys said about my head situation and building my corvette engine ect..
As you know I have an 81 corvette that looks wonderful, problem is, it is a slug. This is why.
350 L48 (190hp) DOG 8.2 cr
350c trans
Electronic Q-jet
Electronic advance Dist
2.87 rear gears
3600lb car.....

Well...I took the heads off, and my buddie milled them for 20bucks(owns a machine shop) I was gonna spend money on better heads, but I think the rest will come into play.

Removed the factory exhaust today and the big cat..
Ordered headers, that should fix the exhaust problem

Pulled the rear out, and have it on ther bence at work.
Ordered 3.73 gears for it today

Pulled the cam out 2 hours ago (very small cam..something like 390lift and 190dur(stock smog cam)

Ordered crane cam #csx4 250h-11
specs are 206-214 @.050
432-453 lift
lobe center 111

I have a edelbrock performer intake and I just rebuilt a holley 750 daul feed single pump carb.( I hope it isn't too big, but it was free.)

And also have a normal vacume advance dist, which I think I can just put a simple curve kit in to advance it faster. Not sure whick one to get..Any ideas?

What do you think?? I am not looking to run 10's, but I think with this set up in a 1981 corvette, it should pull like hell to about 4000 rpms and put you back in the seat.
I am not sure what kind of HP numbers it will make, but if someone has an idea, I would love to know.

Also, do you think with the set up I have, pulling a 14 sec 1/4 mile is far fetched??? It might not sound like a hot rod with the cam I picked, but I hope it pulls out like hell. I hate those guys that have the big 550lift 330 duration cams, and they sound great, but fall on thier face. JMO

Well, need some input, hopefully I did well, cause all the stuff is ordered!!
ha ha ha

In my opinion, the c.r. of 8.2 is a little light for the cam you have chosen, but if it were mine, I'd install Rhoads lifters on the cam. They'll bleed down at rpm's under 3,500 and take away about 10 degrees less effective duration. On the other side of 3,500, they'll pump back up and give you all the cam back.
http://www.rhoadslifters.com/why.html

Sounds like a pretty good combination.Only thing I would add would be to have your buddy do some pocket porting while he has the heads(depending on which heads your using)but if they are decent flowing heads(for that combination) I wouldn't touch them. With some tuning and traction you might reach 14's.One thing for sure,you'll be able to tell a difference in the car's performance.

sorry about the cam..It is a comp cam not crane
4x4 cam
specs are 206-214@ .050
432-453
lobe center of 111
# csx4 250h-11

Any other suggestions tech inspector..And buy the way, thank you, I orignally was gonna put a 268 cam in this, but you told me to call the hotline, and tell them what I had ect...and what I wanted
Should the 2.87 gear that I had feel like a big difference with the 3.73??
I hope I picked the right ones. I wanted to feel it when I pulled out.

I have the block out. I could pop a set of cheater pistons in it(small dome) if you really think that will make a difference with the cam and the cr..

i think the cam is ok but i think the carb may be to big for you set up how much did you cut off the heads ? a bit loose on the stall may help on the carb. o deck the block and run a flat top piston

I've got a Comp XE256H cam. You couldn't ask for a more torquey cam, you'll make more torque with the larger 256 duration than the 250. The 250 is more of a 283 cam. I strongly suggest you do more to raise your compression ratio. I used Vortec heads to net me 9.26:1. In a 4000 lb truck with 3.07 gears, 29.6" tires, and a stock converter I ran a 15.37 and 90.5 mph. That was while shifting 800-1000 rpm short of redline, too. With 3.5 or 3.73 gears and valve springs (to give me the confidence to rev to 5500), I feel the truck would run mid-14's. Heck, I'm crossing the finish line in 2nd gear and I've got a 3rd one just itching to go.

I was gonna go with the xe256 cam, but the guy at comp cams said this 4x4 cam will pull like hell. I told him I was after torque, because it was a heavy car, and I even suggested the xe256 cam, but he told me this 4x4 cam is even more a torque monster. I dunno. So many choices, but so little extra cash. But in all honestly, I am not looking for a race car, just a toy, but a toy that can get out of its own way. I am really hoping going from a 2.87 rear to a 3.73 with the cam, ect will make a difference.

well they make the cams so they should know ? and the jump on the gear you well see i stil l would o the deck on the block

I just hope you don't run out of gear with the cams pulling range.

yes so how tall on the tries

I just swapped from 2.56 gears to 3.73s.... major change

Originally Posted by jchrisd

sorry about the cam..It is a comp cam not crane
4x4 cam
specs are 206-214@ .050
432-453
lobe center of 111
# csx4 250h-11

Any other suggestions tech inspector..And buy the way, thank you, I orignally was gonna put a 268 cam in this, but you told me to call the hotline, and tell them what I had ect...and what I wanted
Should the 2.87 gear that I had feel like a big difference with the 3.73??
I hope I picked the right ones. I wanted to feel it when I pulled out.

I have the block out. I could pop a set of cheater pistons in it(small dome) if you really think that will make a difference with the cam and the cr..

No, you're real close, I am just trying to optimize the combination with the Rhoads lifters. The 3.73's are gonna make the biggest difference. 4,500 rpm's with a 88" circumference tire (28" tall) will get you to 100 mph (in a hurry).

Comp provided the lowest rpm gain cam (600 rpm's) at the highest valve lift they could. If they could have spec'd a shorter cam, they would have. The Rhoads lifters will optimize the cam. Use 'em. You'll be happy with 'em. This motor will tear the tires off the car at low r's.

Comp has dyno sheets for the XE250H and the XE256H cams on their website.

http://www.compcams.com/Technical/Dy...50H-10_001.asp
http://www.compcams.com/Technical/Dy...56H-10_001.asp

They make pretty much identical power curves with the same peak torque and horsepower at the same engine speeds. The 256 just carries itself for a few extra rpm. That means you can stay in your lower gears longer to help get that heavy car rolling.

Horsepower is what gets you down the track, not torque. I can exhert just as much torque as my engine to the wheels of my truck and more. Yet, I cannot exhert that torque fast enough (horsepower) to get it rolling at any appreciable speed. If you have a car running at a certain mph and two engines running at the same horsepower output, yet one is running at 3000 rpm and the other is running at 6000 rpm, they are both putting the same amount of torque to the wheels even though the 6000 rpm engine is making significantly less at the crankshaft. Maximize your horsepower and generate your torque with gearing (those 3.73's are going to be plenty sufficient).

Here is a clip of my truck running a 15.372: http://videos.streetfire.net/search/...E19507E2C1.htm
By using the detent to keep the truck in 2nd gear, I was able to increase the MPH from 88 to 90.5 in a later run, but I spun the tires bad off the line.

The combination I gave is entirely capable of getting a 3600 lb Vette into the 14's, especially with your gearing and tires. No slippery converter or high octane gas required. It was topped off with an out of tune Q-jet and a stock HEI ignition.

this is awsome. i have a story for you. a friend of mines dad built a 79 corvette 350 30 over (355) vortec heads, flat top pistons (10.0:1 compression) 750 q-jet, all stock ignition, 3.73 rear gear. this story isnt one of those i new this guy that new this guy. i actually rode in this car. at a stand still this car jumped out of the hole. then we proceeded to go down town by highway in a 55 mph zone we were doing 60 came up on this car and slowed to follow i was just along for the ride but i had a feeling he was gonna pass this car. yup he did i looked at the speedo just b4 he punched it at 55mph we were what seemed instantly at 80 mph and it set me back in my seat like the seat was pulling me in. just a story. but if u start doing head work just like i tell every 1 check the price of the work then check the price of the vortec heads. oh yeah he used that extreme 4x4 cam dont know the numbers but that car had an awsome thumpy idle and went like HHHHEEEELL666

Hey 383..If you can, find out which cam he used.I think I am on the right track with this set up. Only thing is I am still running about 8.2 compression ratio. I wonder if I HAVE to boost my CR in order to have the big power. I didn't go with the vortec heads and intake, but I wonder before I put it back together if I HAVE to go that route. Nothing for nothing, but the car isn't really worth more than 12 gran, and it is worth LESS the more I chop it up. I plan on selling the car next year, and getting a real car, but this is fun for now.
I thinl the 3.73 rear is the major ticket to be honest.