I have a 88 Formula with disc/drums. I want to change my master cylinder. My ? is what size is the bore? I want to repace mine with a WILWOOD high volume aluminum one. They have 3 diffrent sizes 3/4, 7/8,and 1 inch. It is the one on page 151-k in the new JEGS catolog. Please help or let me know of my other choises. The price isn't bad for $49.99

 

Reguardless of bore size you could have a problem installing the new master cylinder. All third gen master cylinders have the outlet ports on the inside (towards the engine) because there's no room against the shock tower. The majority of all the aftermarket master cylinders have the outlet ports on the other side. If you use one of these, you'll have to fabricate or bend the brakes lines to reach the new port location.

Your 88 will also have metric bubble flare fittings so they won't fit in the aftermarket master cylinder without adaptors or having the fittings changed.

Those high volume aluminum master cylinders are also for custom applications. They won't bolt to a factory location.

 

Thanks, I wanted to change because the stock seems cheap and move when I take the cover off. I also like the pre 82 style that was on the F-bodys.

 

And where/what can I get a new paporting valve besides the dealer?

 

I can not beleave no one has done this

 

TTT

 

Well, that plastic reservoir is definately strange compared to the old metal ones, but it does work... if it didn't, none of us would have them.

You could buy an adjustable prop valve from Wilwood or similar, but the only place you'll find a new factory-style prop valve is the factory.

The J50 m/c (drum/disc) has a 24mm bore. The J65 m/c (82-88 4-wheel-disc) has a 25.4mm bore, which is equiv to one inch.

 

thanks