I have recently got my 68 camaro up an running and am a little disappointed whith its power. it has the original 396 that has been completly gone thru(bored .40 over,3 angle valve job,balanced,9.3 hyper? pistons,cam is int-.500 ext.-.507 duration .222 ex.235 with a centerline of 115) intake is a weiand stealth, carb is 750 Holley vac sec, GM HEI with MSD components, Hedman headers, T-400 tranny with i think a stock converter, 3.31 rear end gear ratio. The problem is i hear about this tire roasting power from big blocks but dont feel it in this car. Are my expectations for this motor to high? Im sure i have some fine tuning to do but i just done feel that torque i keep hearing about. Dont get me wrong, it is still alot of fun to drive but i guess i was just expecting more. Any thoughts would be appreciated. Thanks

Have you tuned the carb and timing?

From a carb perspective, you may need to go with a lighter secondary spring that will open the secondaries up a little faster.

Others can help you in more detail with the timing, but you should run around 10 degrees or so initial and 26 or so mechanical advance. Do you have vacuum advance?

Also, that cam sounds a little stout for use with a stock converter. You may need to get a looser one.

A 396 is not going to make huge big block type torque. It does not have the cubic inches. It can make really good power though!
Important - which cylinder heads does it have? Factory rectangular port heads are even too big for a 502 for maximum street torque/hp. The large intake runners kill torque. Great factory head for 396-454 (under 10:1) is the open chamber large oval ports. Very underated!

The camshaft sounds decent but not great. The 115 centerline is not going to make much torque. 109-110 works perfectly for most big blocks.

The rear gear and torque converter are also holding the motor down. Depending on tire diameter 3.73 to 4.11's will work wonders. A good 2500-3500 torque converter with these gears will up the anti!

Tune, tune, tune. I've seen just a 2 degree difference in timing make a 20hp difference!

My car's first time out on the track ran 12.20 at 112 mph. I ended up changing timing and carb jet's until it consistently ran 11.60's at 118 mph. I know holley's well and I thought I had a good baseline when first going out - apparently I didn't!

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8.5:1 11 second 454

[This message has been edited by motorhead (edited 08-24-2001).]

the heads are the original ones, i have a set of 049 heads but was told those would not work with the pistons that i have in there right now. maybe my expectations were just to high for this combo.

Have you changed the advance curve in the HEI the stock ones are very slow and will give the feeling of no torque. Your heads will make more torque than 049s and are really a much better head.



[This message has been edited by oger (edited 08-25-2001).]

maross396,

Your "expectations may have been a little high for this combination", but I would not give up on it just yet. You will be impressed at the difference you can make with just a little tuning, and you will be amazed at the difference you will see if you follow the advice of some of the posts here and change that converter and rear gear.

Mike

maross396: What pistons do you have in this motor? If they are the small domed pistons, they will work with either closed chamber or open chamber heads. I have a 396 in my 69. It is stock with the exception of balanced, and a solid cam, and I can blow the tires right off my car. It does have a 4 speed, but torque is basically all I can manage to get out of my 396. It runs fantastic from idle to about 6000 rpm, but runs out of power at about 5500 rpm. My motor has about 8.5 to 9.0 to 1 compression. I think my heads are holding me back. Also I had a 600 double pumper Holley on mine when I first got it running. It would barely pull 4500 rpm. Feed that big block with some fuel and crank your timing in at 36-38 degrees, and I think you will like the difference! Good luck.

my 454 was a big dissapointment at first and the first year we ran it at the track we only managed a best of 15.8 and we knew there was more in the motor. So we replaced the torque converter (the guy effed up the welding so it stalled at a blazing 1000 rpms) and put in a B&M 3000 and then we finally got the tire spinnin all the time and our times reduced a little bit because of the new found traction problems. Ever since we got our 454 from a poor 18 seconds down to a 13.4 seconds with little changes here and there, swap intakes, torque converter. Its a learning experience in its own to figure out what performs best on your motor and makes it more fun to own.

Rob