Thread: thumper or not????????

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Hi guys i have a 1995 350 chevy with vortec heads stock roller motor i want to add thumper or muther thumper cam . will i need to changes springs ? if so what else needs to be dune. and i have a 700r4 be hind it.stock torc converter .

In order to take full advantage of any cam, one should use a spring that is suggested by the manufacturer. You also need make sure you have sufficient P to V clearence.

Keith...

Here's the cam card for the thumpr....
http://www.compcams.com/Cam_Specs/Ca...?csid=107&sb=0

And here's the one for the mutha thumpr....
http://www.compcams.com/Cam_Specs/Ca...?csid=108&sb=0

These will tell you everything you need to know to run either of these cams.

I thought it might help some of you to run a DynoSim with the thumpr cam and a few different sets of heads. The motor is a 355 Chevy, 10.3:1 static compression ratio, 1 5/8" long-tube, equal-length headers, RPM intake, 750 carb. The first number is hp, the second is torque. Heads are listed best to worst on this particular motor. *means aluminum. The cam is a 12-600-4 CompCams Thumpr, .479"/.465", timing figures @ 0.050" are 11.5/35.5/52.5/8.5, 102/112/107, cam installed straight up.

1* Patriot 225, 547/6500, 504/5000 (Please, no groaning from you Illinois guys about this. The dyno just really likes this head, so get over it)

2* Airflow Research 180, 474/6000, 470/4500

3* Edelbrock RPM 170, 453/6000, 463/4500

4 Dart Iron Eagle 180, 450/6000, 461/4500

5* Canfield, 448/6000, 458/4500

6* Patriot 195, 438/5500, 453/4500

7 World Sportsman II, 434/5500, 453/4500

8* Holley Systemax, 433/5500, 454/4500

9 GM L31 Vortec 1.94/1.50, 426/5500, 446/4000

10* Brodix -8 Pro, 424/5500, 450/4000

11 GM 462 casting 1.94/1.50, 389/5000, 437/4000

Great article on the Street Rodder Website. Great link Tango I am going to install a "mother thumper" camshaft in a small block chevy I am going to be building for my Graffiti coupe soon. If you want to hear all of these "thumper" cams idling go to www.youtube.com and type in "thumpr cams". It will bring up a post by Comp cams which has all of these cams idling on a dyno. Great way to hear what your idle will be like! Good luck! Don jr.

Probably depends on whether you're after sound or performance.... The cam card for the smaller cam states you will have to change springs for sure, and should go with a higher stall converter... As Tech mentioned, better heads would be a definite consideration. The Street Rodder article shows some nice power using the AFR 180 heads.....

what do you mean by guys from Illinois?????I don't recall any of my engines running differently when I crossed a state line

Now that you have mentioned it---I do know of 3 different chassis dynoes that can custom tailor your dyno sheet

try driving over the Hawaii state line.

Originally Posted by techinspector1

(Please, no groaning from you Illinois guys about this.)

Okay, okay, no groaning. But I'll bet our governor is a bigger crook than your governor! LOL!!

Actually my rear engine dragster and most of the Pinto funny car ended up in Hawaii

Originally Posted by rumrumm

Okay, okay, no groaning. But I'll bet our governor is a bigger crook than your governor! LOL!!

Only difference is....yours got caught. Mine is still runnin' loose.

I like the noted engine vacuum for the smallest Thumpr cam ...

Originally Posted by moter

I like the noted engine vacuum for the smallest Thumpr cam ...

Yup, 9" of vacuum is really poor--wouldn't plan on having power brakes on the car......

If engine vacuum is not an issue than I totolly suggest a Thumper Cam line up. Performance and idle quality are important to every hot hot rodder but we all know that every rod is a compromise. My rods always have manual brakes (with no problems) and a high stall converter (or a stick) which makes the rad cam not a problem. Over camming a hair is fine with me. If you are looking for max performance in a drag strip situation then every choice you make is so important but street is a neat chance for us all to do what we feel. I feel on the street that we all look to have a great idle with great peformance. The Thumpr series delivers that with everything I have seen and I will go with one. Don Jr.