72 GMC - Engine hitting firewall...need advice - Page 2 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

454_72_4X4 · 12-26-2006, 04:06 AM

Here's mine.

Troy-Built · 12-26-2006, 08:51 AM

Try the simple things first. Like what was said before look at your cab mounts. It doesn't take much of a drop in the bushings to cause your problem. Also, look at your transfer case mounts they are usually smashed down from all of the weight over the years. Put some polyurethane transmission mounts in place of the old ones and see what that does. If you haven't replaced them already I am sure it needs it. Cheap and easy fix.

ducmons · 12-29-2006, 11:42 PM

i got sick, so I haven't been able to work on it.

here is where its touching. Thanks to all for the advice.

68C15 · 12-30-2006, 08:58 AM

if you are careful you can remove the valve covers and rear rockers. lay rags over the heads and use the 2 hammer method of massaging the firewall.

**chevy71super** · 12-30-2006, 11:34 AM

The main cluprit is the tall valve covers. I have a set on my 71 4X4 and they barely clear. I can't stick my finger between the cover and the firewall and the difference between mine and yours is the corners are more rounded on mine. Your valve covers look great but the easiest solution is to find ones that clear.

12-26-2006, 04:06 AM	#26
454_72_4X4 Registered User Join Date: Apr 2004 Location: N.E. MO Posts: 1,749	Re: 72 GMC - Engine hitting firewall...need advice Here's mine. __________________ 72 C20 4X4 454 4 speed 89 Trans Am (was) 305 TPI 700r4 93 C1500 2wd Extended cab 350 700r4 98 Sonoma (TPI outa the Trans Am) 03 Yamaha 660 Raptor 03/04 660 Raptor 07 700 Raptor 85 Honda Odyssey

12-26-2006, 08:51 AM	#27
Troy-Built Registered User Join Date: Mar 2003 Location: Perrysville Indiana Posts: 258	Re: 72 GMC - Engine hitting firewall...need advice Try the simple things first. Like what was said before look at your cab mounts. It doesn't take much of a drop in the bushings to cause your problem. Also, look at your transfer case mounts they are usually smashed down from all of the weight over the years. Put some polyurethane transmission mounts in place of the old ones and see what that does. If you haven't replaced them already I am sure it needs it. Cheap and easy fix. __________________ 69 Chevelle SS 375/396 TKO 600 71 Suburban 3/4 4x4 402 5-speed (project) 68 chevy C10 shortbed 327 5-speed (project) 72 Blazer 4x4 400 4-speed (wifes project) Numerous 67-72 parts trucks

12-29-2006, 11:42 PM	#28
ducmons Registered User Join Date: Jul 2006 Location: Seattle Posts: 56	Re: 72 GMC - Engine hitting firewall...need advice i got sick, so I haven't been able to work on it. here is where its touching. Thanks to all for the advice. Attached Images

12-30-2006, 08:58 AM	#29
68C15 blood type; Retumbo Join Date: Jan 2004 Location: next to my reloading bench Posts: 10,269	Re: 72 GMC - Engine hitting firewall...need advice if you are careful you can remove the valve covers and rear rockers. lay rags over the heads and use the 2 hammer method of massaging the firewall.

12-30-2006, 11:34 AM	#30
chevy71super Registered User Join Date: Jan 2002 Location: So Cal Posts: 658	Re: 72 GMC - Engine hitting firewall...need advice The main cluprit is the tall valve covers. I have a set on my 71 4X4 and they barely clear. I can't stick my finger between the cover and the firewall and the difference between mine and yours is the corners are more rounded on mine. Your valve covers look great but the easiest solution is to find ones that clear. __________________ 71 Cheyenne Super 4X4 SB 72 Cheyenne Super 4X4 SB 72 Cheyenne 4X4 SB



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