Big Block Hitting Firewall Issues

[ecgate]

I went to set my cab today on my 67 and it is hitting the valve covers on the firewall. My engine is sitting 2 inches too far back. Im running an electric fan and so I had to move the engine to the rear mounting holes on the frame for the engine mounts in order to have clearance for my electric fan setup. I don't want to get rid of the electric fan nor do I want to change my long water pump to a short water pump and move the engine forward because then I would need to get a new driveshaft also. I don't feel like paying for everything twice. So has anybody cut there firewall to make more clearance for the engine to fit. It looks as if It would be the cheapest and easiest fix. I just don't want to cut up my firewall if Im overlooking a simple fix. Any ideas or info on my situation would be greatly appreciated.

[ecgate]

Here is a pic of the areas I would have to cut and patch.

[67ctener]

Are you on big block mounts? I figured big block and long pump you could run electric fans no problem. Personally I'd stay clear of cutting the firewall
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[67ctener]

Short valve cover may also help a little
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[ecgate]

Originally Posted by 67ctener

Are you on big block mounts? I figured big block and long pump you could run electric fans no problem. Personally I'd stay clear of cutting the firewall
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The motor mounts im running are POL's tubular mounts that are supposed to move the engine slightly forward for the hei purposes. Im not too worried about cutting the firewall and making it look good. Its the other problems that Im not aware of now that may pop up in the future that Im worried about. My long water pump setup isn't doing me any favors either. Do you know how much space I would gain with a short water pump?

[El Campo]

I have helped cut a firewall before. Worked just fine. My BB almost hit but short valve covers helped. I too have a long water pump and electric fans. And man that is a tight fit!! I havent put truck all back together but I sectioned the core support and am moving the radiator forward about an inch to gain some clearance. A short water pump will gain a TON of room. I cannot remember the actual numbers right off but I think its over an inch.

[Fitz]

Originally Posted by ecgate

The motor mounts im running are POL's tubular mounts that are supposed to move the engine slightly forward for the hei purposes. Im not too worried about cutting the firewall and making it look good. Its the other problems that Im not aware of now that may pop up in the future that Im worried about. My long water pump setup isn't doing me any favors either. Do you know how much space I would gain with a short water pump?

You have the wrong motor mounts. Use the stock big block mounts and stands and it will fit just fine without cutting the firewall.

[ulakovic22]

+1 on the wrong mounts. I used the POL mounts at first as well and was running into oil pan and header issues when I switched to a BBC. I'm now using 68-71 BBC mounts and everything fits perfect.

[Tom Vogel]

You shouldnt have to move the engine back to clear electric fans. I even have a supercharger (wide belt) as well as All the possible accessories, and my fans still clear the pulleys.

[ulakovic22]

Now that I think about it, when I switched to the 68-71 mounts, it actually moved the engine back and gave me more clearance for fans/pump/radiator.

[70CHEVYBB]

ship me the big block and I will throw it in my truck to see how it fits. lol
I already have one, here is a pic of mine and I made my own tube mounts.

[chevy72blu]

I ran into the same issue and went to a short pump setup in order to make my e-fan fit. It was a pain to track it all down, but it worked. I was able to recoup most of the cost by selling my long pump accessories


In either case, I would much rather have a D-shaft shortened that cut the firewall. Just my .02

[Fitz]

Originally Posted by 70CHEVYBB

ship me the big block and I will throw it in my truck to see how it fits. lol
I already have one, here is a pic of mine and I made my own tube mounts.

That serpentine belt system looks suspiciously familiar.....

[El Campo]

Indeed it does! I dont know if anyone would ever put on a LWP on purpose if not for accessory drives like this haha

[70CHEVYBB]

I would love to run electric fans but I do not have room for them. I let my trans dictate the placement of my engine. I did not want to cut the drive shaft or change shift linkage. I need a shroud cause it will hit 200 after a 15 or 20 minute idle. down the road it runs 180.

[ulakovic22]

You don't need much roon for electric fans, maybe a few inches. Let me see if I can find a picture of my setup.

[Fitz]

Originally Posted by 70CHEVYBB

I would love to run electric fans but I do not have room for them. I let my trans dictate the placement of my engine. I did not want to cut the drive shaft or change shift linkage. I need a shroud cause it will hit 200 after a 15 or 20 minute idle. down the road it runs 180.

With my engine in and the belt drive fully assembled I had 3 inches from the face of the crank pulley to the rear of the core support and about 5 inches from the surprntine belt to the core support. Not much room for a 4 row radiator.
When I installed my rad I trimmed the opening in the rad support and moved it forward about an inch to gain room for my fans which are 3.5 inches from the face of the shroud to the back end of the fan motors. Between the motors it's 2 inches even. A little careful measuring and I was able to get the fans in and still miss the surpentine belt setup I have.

Recessing the rad into the rad support takes some sheet metal work and some welding BUT you should be able to gain an inch or so.

[ecgate]

Well here is my story and Im sticking to it. My POL engine stands does move my motor forward(more than stock 68-71 BBC stands. If I moved my motor to the front engine mounting holes on the frame the long water pump pulley will hit my electric fans. I would need a short water pump and all new brackets and pulleys and a new drive shaft. So I cut my firewall. Did I want to do it? No. But I didn't want to spend the money on the brackets, pulleys, driveshaft, ect....... In the long run I don't think its going to bother anything other than the fact that it isn't factory correct but there is a lot of stuff on my truck that is custom. I guess that this is just going to be added to the list. Thanks to everybody that chimed in with any experience or advise on the situation. When im done Ill try to post some pics of the finished product.