Big Block Tubular Mounts

[Street Sweeper]

OK - so I've been reading up on the motor mounts/perches some of you have used to install your BBC's in these trucks (thanks, by the way - this site is great - and you guys are so knowledgable). I decided to go with tubular mounts from Performance On Line. I know I have to trim the top flange of the frame to make them fit. I also know that those of you that I've been able to find on here that have used them - have mounted them in the rear holes (like the POL "instructions" say you can).

Before I start grinding on my frame I just wanted to see if anyone has had any issues mounting these things that I need to be aware of going in (maybe I should have asked before I bought them - right?).

I'm a little concerned that I won't have enough of the bottom pad on the crossmember in the rearward position (see pics). I'm also a little concerned about distributor/firewall clearance (I really don't want to have to hack up my firewall if I can keep from it).

I guess I'm just looking for some confirmation / reassurance from those of you that have used them -

1) Mounting in the rear holes is best - right? (OK, keep it clean . . . ) -
2) Contact on the crossmember will give me the support I need for the BBC, right? -
3) Mounting in this location won't create firewall clearance issues -
4) Did you only use one bolt on the bottom pad - or drill a second one? -
5) There really is "no replacement for displacement" - so I should go ahead and do this - right?

[Chevy Fleetside]

You should bolt them up to the BB and mock it up to find out. I did cut knoches in my firewall to make the BB set back and there is plenty of room for the dist. I used a jig saw with a metal blade in it to trim back my frame.

[198plus]

I use the same perches as you in the back holes and had no HEI to firewall clearance problems, as far as valve covers you will be fine as long as you use BBC stock covers. How ever if you use the tall valve covers you need to split the firewall on each side and roll in for clearance. I also used a short water pump on mine for radiator and fan clearance, it worked out just perfect with clutch fan..........Hope this helps.

[Chevy Fleetside]

Mine didn't fit with the short BB valve covers. I do have an 89 block but I would think they would be the same as the older ones, unless I am wrong.

[198plus]

I have heard the same thing before, that's why I mocked mine up like you suggested

Originally Posted by Chevy Fleetside

Mine didn't fit with the short BB valve covers. I do have an 89 block but I would think they would be the same as the older ones, unless I am wrong.

[66farmer]

I used the rear holes and the tubular mounts. I used a MSD dist no problem as for the valve covers I used stock 502 covers and I had to massage the fire wall a little.

[Street Sweeper]

Thanks guys. Nothing helps like the voices of experience.

This is my first time trying a swap like this so all the info really helps.

From the sound of things I should be OK. My engine is an older big block with the shorter valve covers. Right now it has the longer water pump - that may need to change. We'll be swinging it over to mock everything up this weekend.

Will try to post some pics of that . . .

[198plus]

Those tall valve covers in the pic will not work without some firewall massaging.

Originally Posted by Street Sweeper

Thanks guys. Nothing helps like the voices of experience.

This is my first time trying a swap like this so all the info really helps.

From the sound of things I should be OK. My engine is an older big block with the shorter valve covers. Right now it has the longer water pump - that may need to change. We'll be swinging it over to mock everything up this weekend.

Will try to post some pics of that . . .

[Chevy Fleetside]

My BB set back with a Mallory HEI unit installed. Plenty of room. You can kinda see the red cap back there.