I am having an issue with my engine and transmission angle being too steep. I am installing a 455 into a 68 Cutlass using the 350 frame mount pads and the anchor 455 engine mounts. The transmission is a Tremec TKX 5-speed and I’m using an Energy Suspension transmission mount supplied by Silver Sport Tranmission, who I bought the transmission conversion kit from. I’m also trying to utilize the stock crossmember.

The issue I’m having is with the stock crossmember the transmission sits at 4.59° downhill. If I jack the transmission up to where there’s about an inch of space between the Energy Suspension mount and the crossmember, I can get it to about 3° (see pictures below).

I also purchased an aftermarket G-Force crossmember, which I tried as well, but that ended up being even lower with a 6° downhill slope. Doh!

In the pictures I have my digital angle meter sitting on top of the transmission. Just an FYI when I put the digital meter on the front of the harmonic balance it’s about 0.1° steeper than sitting on top of the transmission. So the flat spot on the transmission gives a pretty accurate measurement of the angle I’m dealing with.

Should I try to put some type of block spacer on top of the stock crossmember or is it an issue with the engine mounts? I’m pretty sure I have the engine mounts correct. I read the engine mount threads a few times. Maybe a different crossmember? Anyone know of a crossmember that sits up about an inch higher?

Sorry for the long post, but lastly, if I do crank the transmission up an inch am I going to have clearance issues with the body / trans tunnel?



3° downhill notice the large gap (approx 1 inch) between the transmission mount and the stock crossmember.

With the transmission mount sitting on the stock crossmember I am at 4.6° downhill. Too steep in my opinion. Even looks wonky…

 

How much space is there between the oil pan and the saddle in the frame?

 

The combination of 350 frame mounts and 455 engine pads is likely the culprit. There are lots of threads on here about this subject. Use one or the other but they both have to be the same. Use teh search feature and you should find one of those threads.

 

I can just about get my fingers between the saddle and the oil pan. I’m gonna say 1/2 to 3/4 of an inch.

 

I thought about that, but I researched it quite a bit and I think I have the right combination. I may have worded it wrong in my post, I had the other frame pads and couldn’t get the engine to sit into the bolt holes. Wasn’t even close.

 

You definitely shouldn’t be able to fit your finger’s between. you should have roughly a 1/4” space between give or take, I’ve seen it as tight as an 1/8” to as much 3/8” I agree with real olds man you may have the wrong pad mount combination…

 

I just went out to get a more accurate measurement and it looks like it’s just shy of 1/2 an inch. I couldn’t get my whole finger underneath, but I was able to slide a Milwaukee sharpie underneath there and it was a pretty tight fit. The Milwaukee sharpie measures just under half an inch 15/32.

I’ll check into the mounts, but I’m pretty sure I have the right ones. Even if I were able to drop down the engine another quarter of an inch (with diff pads or motor mounts) I would still be off 3/4 of an inch on the transmission mount.

There’s only two possible combinations for that engine as far as engine mounts go and I kept the same engine mounts, but swapped out two different sets of pads, because the first set of pads wasn’t even close as far as the bolt that goes through to secure the engine mount to the engine pad. The bolt holes were off like an inch low on the first set of pads, I tried. The second set of pads aligned perfectly. Although those pads came off of the same frame, but from a 350 that I believe was the original engine.

 

#1. Get something figured out with the transmission cross member and mount between the transmission and cross member.
#2. Get your 3 degrees angle with rear transmission mount and cross member installed.
#3. Then check the front clearance.
The engine/transmission will cantilever off the engine mounts......lift the transmission output shaft and the harmonic balancer will move down. Think about it.

 

Thanks for the insight guys. Ralph. I thought about the tilting effect as well. I will definitely check the clearance once I get to my 3° goal. I found some transmission mount spacers. I might try, but I was worried about bringing the transmission up to high for tunnel clearance. Supposedly with the new Tremec TKX you don’t have to modify the trans tunnel, but I hear it’s a tight fit.

 

If you really have the original 1968 frame pads, you had better be using Anchor 2261 motor mounts. Even the 1968 Hurst/Olds used these same mounts on the 455. As for your non-original trans and cross member, there is no way to know what height the trans mount needs to be. Shim as required to get the correct angle.

 

Good morning Joe. Thank you for your insight. Really appreciate your expertise. Yes, I’m using the 2261 Anchor mounts, Thanks to your motor mount post.

The only reason I had to change out the pads, was because Motor City Muscle Cars originally sent me the wrong pads. They have them listed incorrectly on their website. I tried to return them, but they refused since it was over the 60 day return window. I reverted back to the original pads, but had to sandblast them and paint them up. One was tweaked a bit and I had to straighten it, so that’s why I “tried” to order new ones.

FYI, check your parts stock pile. These guys don’t care if stuff is on back order for a year, but boy if you don’t return them promptly… see ya! Sorry, I had to rant for a moment.

Either way, I think I need a 1 inch spacer between the stock crossmember and the Energy Suspension transmission mount. Anybody see any issue with this? I’m gonna buy grade 8 bolts, with lock washers and use thread lock, but I worry about 1) tunnel clearance and 2) the connection point being raised up an inch. I’m running a 600 ft/lb 455.

 

You are concerned with the dimension from the crossmember support to the transmission centerline. You want this dimension to be no more than the OEM distance.

Call your transmission supplier, Silver Sport, and ask how this dimension compares to the OEM dimension. They seem to be quite knowledgeable people and should be able to answer easily.

 

“Call your transmission supplier, Silver Sport”

Thank you. I called Silver Sport this morning and they said that if I use a 1 inch spacer, the transmission will hit the tunnel.

I didn’t ask how much play there is there, compared to OEM, but it sounded Like there wasn’t much. The tech person I spoke to said “everybody gets hung up on driveline angle and they supply the correct height mount for my application”. lol. I guess I get hung up on driveline angle when it’s over 4 1/2°.

I think I’m going to shim it with washers and mock it up until I get the body on. Then I’ll see where I am and adjust as needed. Hopefully there’s a little bit of wiggle room and maybe some ball peen hammer taps might be necessary.

 

Can I ask what angle you’re frame is at?
How is it being supported?

Another thing is to make sure you’ll have room to clear the trans when you put the body back on.

 

The frame is sitting on six heavy duty snap-on jack stands. The stands have been shimmed to make the frame level corner to corner and side to side. As level as possible for a garage floor/Jack stand set up.