Thread: Starting & Tuning up 540BBC with Holley DP 750's and B&M 871 Blower

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I would re-think the OD trans. If the R's come down too far, with the cam that's in there, the motor is likely to load up, foul plugs and begin coughin' back through the blower. That's where things are gonna get REAL EXPENSIVE, REAL QUICK. I don't know for sure, never had a blown BBC with a radical cam, but I'm bettin' that the best plan would be to leave the 'Glide in there and maybe even consider more rear gear. The only reason you might want an OD trans would be for fuel mileage and you darned sure won't get any fuel mileage with that combination, regardless of gears. If you want fuel mileage, swap in a stock 305. COMBINATION, COMBINATION, COMBINATION. Seriously, before you screw the pooch, talk with some other fellows who have this combination on the street and get their recommendations. Sounds to me like you're trying to turn a race horse into a plow horse.

"Figure transmission 2nd gear out"
The builder may have modified the valve body to a manual shift mode only, by blocking the shift valve open. If that was done, then there will be manual shifting only and whatever gear you left it in when you stopped, is the gear you start out in when you leave again. Manual shift means manual shift, up and down. Look and see if there is a vacuum line from between the blower and the carbs, to the transmission. I'm bettin' there ain't one. I don't see one in the pics.

"Install Brake Booster"
I wouldn't expect this to work out real well and would suggest an electric vacuum pump to work the booster can....too much cam, very little vacuum....
http://www.summitracing.com/parts/sum-760152
Or a complete Hydraboost system if there is a power steering system on the car.

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Originally Posted by techinspector1

I would re-think the OD trans. If the R's come down too far, with the cam that's in there, the motor is likely to load up, foul plugs and begin coughin' back through the blower. That's where things are gonna get REAL EXPENSIVE, REAL QUICK. I don't know for sure, never had a blown BBC with a radical cam, but I'm bettin' that the best plan would be to leave the 'Glide in there and maybe even consider more rear gear. The only reason you might want an OD trans would be for fuel mileage and you darned sure won't get any fuel mileage with that combination, regardless of gears. If you want fuel mileage, swap in a stock 305. COMBINATION, COMBINATION, COMBINATION. Seriously, before you screw the pooch, talk with some other fellows who have this combination on the street and get their recommendations. Sounds to me like you're trying to turn a race horse into a plow horse.

I have decided to stick with the powerglide. But the original plan was to change the rear gears out to a higher gear and install 700r4. Not looking for mileage as much as looking for drivability around town. Just looking to take the car into town for dinner and maybe a movie.

If there is a vacuum line run from the motor to the transmission. Could the vacuum not be enough for the transmission to shift. In other words the cam is creating another vacuum issue?

Originally Posted by techinspector1

"Figure transmission 2nd gear out"
The builder may have modified the valve body to a manual shift mode only, by blocking the shift valve open. If that was done, then there will be manual shifting only and whatever gear you left it in when you stopped, is the gear you start out in when you leave again. Manual shift means manual shift, up and down. Look and see if there is a vacuum line from between the blower and the carbs, to the transmission. I'm bettin' there ain't one. I don't see one in the pics.

There is a location on the power glide for a vacuum but nothing is hooked up in this location. I have not had much time to play with the car to inspect the transmission. But I do know first and reverse work.

Originally Posted by techinspector1

"Install Brake Booster"
I wouldn't expect this to work out real well and would suggest an electric vacuum pump to work the booster can....too much cam, very little vacuum....
http://www.summitracing.com/parts/sum-760152
Or a complete Hydraboost system if there is a power steering system on the car.

Wouldn't expect this to workout well…. Not sure why not?
Yes I do plan to run an electric vacuum only because I have run large cam motors before.

The Hydraboost system is a good option. It does create extra power steering lines within the engine compartment. If you have ever run this system did you notice any lag in the steering after the extra fluid is added? Also this would eliminate the electric vacuum pump.