So I'm getting ready to swap a 540 BBC into a small block car, no a/c, but does have power brakes and power steering. I know the engine swap has been done by many on the forum and its relatively simple, but Ive heard that tall valve covers (need them due to lift) will not clear the oem 9in booster, I can't seem to find the link explaining which 7 in booster has the ideal push rod and mounting stud length and what is expected when swapping it. And yes I know the hydro booster would be ideal but not a fan of the price tag it carries.

 

No help. Lightweight master cylinder, manual brakes.

 

It might depend on how "tall".
There are some that are like 3/8" taller that clear the roller rocker polyloks and I believe they clear the booster even with a square back corner, no "slant".
Not sure what thread it was in but it was lately, was probably about the slanted covers.....
https://www.corvetteforum.com/forums...clearance.html

I got my stock height "chromies" to clear the poly loks by trimming the polylok .375": Clears my solid roller no problem, it was the lock on the polyloks.

Or check ajrothm posts, I think he uses the slightly taller stock look ones on his 10 sec ride.

 

Hydroboost.
I got mine here for $125. Got a new master cylinder for $38. With fittings and hoses I'm all in less than $200. Don't go buying those kits from the vendors. Way over priced.

 

I'm copying this over from a word doc I had .. I hope the format is ok my pics tend to come out really big for some reason sorry guys.

My car is a 69 so keep that in mind as well for differences.

I was converting from manual to a 7" power so there could be some stuff in here about that you can disregard, I tried to remove it all.

• If you have anything less than 18" of vacuum the 7" booster will really struggle to assist pedal effort. I am in the process of adding a vacuum pump to help correct mine.
• My booster and master also move the location of the brake lines down to the distribution block so you will have to deal with making those up as well.

The TuffStuff 7" booster and master cylinder combo is about 2" shorter overall and 2” narrower in diameter making it more compact on the firewall and by the engine.

Tuff Stuff Performance 2122NA
Tuff stuff 2071 master cylinder
Master Cylinder Bore Size1.125 (1 1/8) Corvette style with 9/16 in. and 1/2 in. fitting on driver side.
Booster Diameter (in)7.000. ( 2222na )

• The 7" booster rod is 1/2" shorter from the base of the booster that mounts to the firewall to the tip of the threads on the push rod. This requires the clevis to be longer or some type of threaded rod to be made up. I chose a longer clevis (see below, more info on the clevis at the bottom of this doc.) as the 1/2" is just not that easy to make up when it comes to threaded rods.

Factory clevis
D = 2" from center of the 3/8" pin to the bottom of the threaded end. Threads are part of the flat stamping material.
A = It uses a 3/8" pin
B = The opening between the pin holes is 7/16"s.
It is 1" wide from the side
Threaded female shank of 3/8 x 24

The McMasterCarr clevis
D = 2 1/2" Threads extend out from the clevis body on a 7/8" shank. This gives you 1/2" of additional overall length in threads. (Its forged steel not cast.)
A = 3/8" pin
B = 7/16"
It is 11/16" wide at the side (allows it to articulate on the pedal better).
Threaded female shank of 3/8 x 24

www.mcmastercarr.com

 

Thank you very much this is exactly what I was looking for, now my last question is was the 4 mounting studs in the same location. I know you went from manual to power so you had to drill regardless but since I saw you had a factory unit next to it I was wondering if that was something you looked at.

 

Its been a long time but the mounting holes for both boosters where the same I recall.

I was able to use the factory Firewall seal with no issues from what I remember.

 

From what i recall the booster mounting bolt patterns are the same. I was able to use the factory style firewall seal for the booster.

I made a pdf out of the word doc instead and tried to attach it to this post.. if that helps any.

 

Thank you once again will be ordering everything soon, can't wait to have this Big block going

 

No need to swap boosters.

Ansen tall valve covers. No issues clearing roller rockers with poly locks. Stock PB booster. No issue getting covers on or off. My old chrome valve covers were already 3/4" taller than stock. Unless you go with some monster tall valve covers, the booster will clear just fine.


Height difference

Old vs new

Clearance

 

I had put one of those smaller booster on for clearance issues (LS1 into a RHD corvette) , I had to put a small extra vacuum tank inline to get the brakes back to normal.

 

Here are the dimensions of the Ansen valve covers. They will clear roller rockers with poly locks. They would not clear a stud girdle.

 

thank you and yes mine are just a bit taller than that got a steal on a pair of gm performance valve covers