Power to manual conversion - Does adpater plate affect pushrod length?

[JMarsa]

I'm doing C5 fronts and Camaro 4th gen rears on my '76 Nova. I currently have power disc/drum brakes but will convert over to a C3 1" Corvette manual master cylinder to cure the big cam hanker'in I've got.

When I use an master cylinder adapter plate to convert from the power booster 4 bolt to the manual master cylinder 2 bolt set-up does the thickness of the adapter plate affect the pushrod length? It seems that a thinner adapter would be better than a thicker one.

Thanks,

--JMarsa

[JMarsa]

This might help someone else down the road...

You don't need an adapter plate to convert from the 4-stud booster mount to the 2-stud manual master cylinder mount.

When not equipped with power brakes, the stock setup for these cars simply mounted the master cylinder directly on the 2 studs that are on each side of the pushrod hole in the firewall. Nuts were installed on the two otherwise unused studs.

The stock 75-79 Nova manual brake setup did use a rather unusual pushrod setup. Instead of having a deep hole in the master cylinder to retain the pushrod (like earlier years), these cars used a master cylinder with a shallow pushrod hole and a special pushrod & retainer. The special pushrod has a built-in ridge/flange near the master cylinder end. The retainer is a cup-shaped piece of metal with a hole in the center that fits through the pushrod hole in the firewall and is held in place by the master cylinder. The hole in the retainer is small enough to allow the pushrod to pass through, but not the ridge/flange near the end of the pushrod. That keeps the pushrod from falling out of the master cylinder when the pedal is released.

If possible, try to get the pushrod & retainer from a 75-79 with manual brakes. You'll most likely find these parts in 6-cyl cars. I believe power brakes were standard equipment in 75-79 Novas with V8's but optional in 6-cyl cars. Even if the Corvette master cylinder you're using has a deep pushrod hole, the stock 75-79 Nova manual brake pushrod should fit since the retaining ridge/flange will keep the pushrod from going too deep into the hole in the master cylinder.