Dropped my '56 off at Cnut's today

[Custer55]

Chad, How much taller than stock are your valve covers? I have my engine mounted very similar to what yours is. About 3/4" forward and just high enough for a 6 3/4 balancer to clear the steering rack. I have plenty of clearance at the firewall with stock height covers but looks like it would get pretty tight with a 1" taller cover in the area where the battery box mounts. I have the trans (Muncie 4 speed) moved up about as high as it will go without tunnel mods.
Brian

[hutchenc]

Lazlo...I think you're right on the mounts I already have so I ordered some new ones (the 3.1114's). I'll re-measure everything after I've swapped those in. I have plenty of room to raise the tranny and the tranny is about 1cm too far forward right now, but I have a suspicion that something is amiss with the Korean made mounts I have now. Hence why I'm replacing them. We'll see what happens. Also, the valve covers I have on the motor are about 3.75" tall...they're pretty tall. I had to remove the passenger side cover to get the motor in...there's absolutely no way it's gonna fit (you can see where it rubbed my nice new paint below). Driver's side is a bit better. I honestly think a different set of valve covers will resolve my problems mostly (other than the tranny/crossmember alignment).

Here's a few pics. I'm not sure what the gap between the motor and rack is right now...I'll have to measure that. I did disconnect the one line that pops up so I didn't damage it.

[chevynut]

Lazlo...I think you're right on the mounts I already have so I ordered some new ones (the 3.1114's). I'll re-measure everything after I've swapped those in.

That's a good first step, but unless they're way off I doubt they'll have a lot of impact. It's a good thing to change though, with as much power as you have.

I have plenty of room to raise the tranny and the tranny is about 1cm too far forward right now,

I think that's where your issue probably is. I think the tranny may be too low in the rear. Theoretically it should be 3/4" forward from where it was, if you had it in the stock position. But it's hard to tell since you didn't have the bellhousing mounts in place. The best thing to do is check the engine angle relative to the main frame rails, and make sure it's 5.5 degrees or less if you can get it. You will have to match your pinion to the engine angle.

I honestly think a different set of valve covers will resolve my problems mostly (other than the tranny/crossmember alignment).

Yes, your valve covers are in BBC territory over past the engine opening in the firewall. A BBC needs 1.5" forward to clear the firewall at the heads.

I'm not sure what the gap between the motor and rack is right now...I'll have to measure that.

If it's more than about 1/4" I'd say your tailshaft is too low and the engine angle too steep.

I did disconnect the one line that pops up so I didn't damage it.

You will probably have to rotate the rack like everyone else has to, and make the lines fit.

Give me a call if you need to.

[Aussienomad]

The long and short of is that I haven't. Neither the stock GTO wheels nor the aftermarket ones I have on it have posed any problems with the bolt pattern...it's been the size of the brakes. Even with the 19's I'm barely clearing the outside of the caliper. These wheels won't be a permanent fixture...I'll move to some Corvette wheels next summer.

The GTO bolt pattern is courtesy of Holden Australia and the bolt pattern they have on the local Commodore/Monaro - same cars as the Pontiac G8 and GTO, and same platform that GM borrowed from down under for the late Camaro. Yes the bolt pattern is different to the "normal" Chevy pattern and will not cause a problem when sitting in the garage. The technical guys down here know about the differences and they are not permitted under any circumstance down here - i.e using a Chevy wheel on that bolt pattern. Either change the bolt pattern on the rotors or use wheels with the correct bolt pattern.
Cheers, Des

[hutchenc]

OK...I got tired of wondering if the new motor mounts would help so I got it all swapped this evening.

Here's where it's at...5.6 degrees (btw, that carb mount pad is flat). That's pretty damn close to where it needs to be. I tried to get the driver's side valve cover on, no dice. I think if I shimmed up the tranny in the rear to about 4.5 degrees, it still wouldn't matter...these valve covers are just too tall. I'm switching them out for a set of short ones.



Also, engine to rack is good to go...I even got the line back on. You guys think this is safe to run like this:





Last, tranny mount holes are about 7mm off...I think I can just elongate the holes and call it good, but I may take the crossmember out and have some extra material added to the end of it for good measure.

[chevynut]

Here's where it's at...5.6 degrees (btw, that carb mount pad is flat).

Is the frame at 0 degrees in that pic? If so it's about where it needs to be. I'd check it at the pan rail or top of the head just to be sure the carb pad isn't cut at an angle.

It looks like you have a lot more clearance than you should have between the damper and rack body. We plan for an 8" damper (worst case) and set the engine as low as we can. We use solid steel engine mounts with 1/2" bolts and set the damper for about 3/8" above the rack body with those mounts and bolts. Then when the actual mounts and 7/16" bolts are installed it should sit 1/4-5/16" above the rack body. What size is your damper? Had I known yours was smaller (if it is) and your valve covers might be an issue, we would have considered setting the engine lower.

I tried to get the driver's side valve cover on, no dice. I think if I shimmed up the tranny in the rear to about 4.5 degrees, it still wouldn't matter...these valve covers are just too tall. I'm switching them out for a set of short ones.

I guess I've never see a SBC valve cover extend out that far to the bend on the firewall. Makes me wonder how it fit before. The engine must have already been quite a bit forward. Did you install the prior engine mounts?

Also, engine to rack is good to go...I even got the line back on. You guys think this is safe to run like this:

I think the rack line is fine as-is. You got lucky on that one .

Last, tranny mount holes are about 7mm off...I think I can just elongate the holes and call it good, but I may take the crossmember out and have some extra material added to the end of it for good measure.

If it's only 7mm I'd elongate the holes in the frame bracket and/or the ends of the crossmember a little. Since the offset is so small, I assume your engine was already set forward from stock. Perhaps we should have gone a little further forward, had we known about the valve cover issue.

Hope the shorter valve covers fix the problem.

[hutchenc]

Lazlo...my damper is 6 3/4" I believe.

Where on the frame should I take an angle measurement...near the middle under the door perhaps?

Also, yeah I was running 3/4" forward mounts before so that's why it's so close now. And yes, I put those in a long time ago...well, not me personally. I think the motor was sitting a little lower. The space between the rack and the motor isn't as big as it seems in that picture...the space between the line and damper is not very much. To the rack I'm guessing it's about an inch. I may shim up the transmission a little to get the engine angle a little shallower.

[chevynut]

Chad, yes measure the frame for level right on the bottom of the main frame rail under the door. Like I said, the 5.5 degrees we set the mounts at is relative to the frame, not the ground.

Here's the way I look at it. Since the engine mounts are low on the block, and the valve covers are high on the block, any increase in engine angle will cause the valve covers to move rearward as well as down. So let's say the frame is 1.4 degrees down in front and you're measuring 5.6 degrees on the engine...your actual engine angle is 7 degrees.

You said the engine is a little (7mm or about 1/4") forward of where it was before based on the tranny crossmember holes. I assume you had a stock engine angle of 4 degrees before, and your valve covers apparently cleared the firewall. So if you went to 4 degrees now, they should clear even better. The point of interference on the driver's side firewall doesn't change as the engine is moved up and down since it's a vertical bend. Not sure what that does on the passenger side.

To raise the tailshaft all you really need to do is make a shim to put between the tranny and crossmember, or between the crossmember and frame brackets. As you raise it the hole alignment will improve a little.

[hutchenc]

Got it...thanks Lazlo. I'll see where it's at. Any guidelines on material thickness per every degree of rise on the tranny?

[chevynut]

Got it...thanks Lazlo. I'll see where it's at. Any guidelines on material thickness per every degree of rise on the tranny?

Not sure Chad but I think it's close to 7/8" per degree depending on the length of the tranny.