Two clearance questions - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**Yukon Jack** · 04-15-2003, 09:18 AM

How much clearance should I have between my oil pan and the engine crossmember? It looked like the small block's crossmember would be fine with the big block but I see that the crossmember is awfully close to the bottom of the oil pan - probably between 1/16 and 1/8" of clearance.

Secondly, the passenger side (edited) header tube closest to the front of the engine has a possible clearance issue. The clearance from the bottom of that tube to the top of the engine crossmember is pretty tight. I've done some grinding removing some material from the crossmember and have about 1/16" of clearance. Do I need more than that?

*Randy70C-10* · 04-15-2003, 09:26 AM

You should be ok. When you gas the engine, the drivers side will torque "up".

**Yukon Jack** · 04-15-2003, 09:29 AM

Whoops, I meant to say it's the passenger side, better go edit that!

Blue68 · 04-15-2003, 02:20 PM

If your motor mounts are new and rubber, you might sag that much in time. The difference isnt' the crossmember but the perch/towers. They differ between small and big blocks.

Blue Beard · 04-15-2003, 02:22 PM

Make sure the right side is also clearing the brake lines.

Mine was touching, heating up the brake fluid.

**Yukon Jack** · 04-15-2003, 02:25 PM

Clear the brake lines real well as well as the hydraulic clutch setup.

GreenMystChevy · 04-15-2003, 03:28 PM

As far as the engine to crossmember clearence, it shouldn't be a problem at all. The engine on my Chevelle sits pretty dang close to the crossmember as well, not quite that close but almost, and that is factory.
If you have new motor mounts, I wouldn't think that there would be too much of a problem with the headers, but after time, some settling might take place. I would personally forget about it but I wouldn't want to mess with getting new headers or different mounts. I'd just go with it until you start to see a problem.

**breeh** · 04-15-2003, 04:29 PM

You must have a different pan than I have because I have at least an inch between pan and crossmember. Maybe the later model pan that you have is different somehow.

GMC71k20 · 04-15-2003, 10:00 PM

hydraulic clutch, are you running a nv4500?

**Yukon Jack** · 04-16-2003, 09:16 AM

No, a CH465. The donor vehicle (89 1 ton) had a hydraulic clutch that I'm using. Should be pretty sweet.

GMC71k20 · 04-16-2003, 04:18 PM

should be, considering my clutch squeaks if i even look at it

04-15-2003, 09:18 AM	#1
Yukon Jack Post Whore Join Date: Feb 2000 Location: Rose Hill, KS, USA Posts: 12,684	Two clearance questions How much clearance should I have between my oil pan and the engine crossmember? It looked like the small block's crossmember would be fine with the big block but I see that the crossmember is awfully close to the bottom of the oil pan - probably between 1/16 and 1/8" of clearance. Secondly, the passenger side (edited) header tube closest to the front of the engine has a possible clearance issue. The clearance from the bottom of that tube to the top of the engine crossmember is pretty tight. I've done some grinding removing some material from the crossmember and have about 1/16" of clearance. Do I need more than that? __________________ 1970 Blazer with a 400 sbc and 4" lift 1980 Pontiac Trans Am, 455 Oldsmobile 2012 Kawasaki Concours 14 Last edited by Yukon Jack; 04-15-2003 at 11:30 AM.

04-15-2003, 09:29 AM	#3
Yukon Jack Post Whore Join Date: Feb 2000 Location: Rose Hill, KS, USA Posts: 12,684	Whoops, I meant to say it's the passenger side, better go edit that! __________________ 1970 Blazer with a 400 sbc and 4" lift 1980 Pontiac Trans Am, 455 Oldsmobile 2012 Kawasaki Concours 14

04-15-2003, 02:20 PM	#4
Blue68 Registered User Join Date: Apr 2000 Location: Frisco, Tx, USA Posts: 606	If your motor mounts are new and rubber, you might sag that much in time. The difference isnt' the crossmember but the perch/towers. They differ between small and big blocks. __________________ http://home.comcast.net/~r.landrum/w...tos.html-.html '68 C-10 LWB, '98 Z-71 350 w/accessories (Serpentine), Edelbrock Performer, Edelbrock 1405 (600cfm) carb, GM HEI, CompCam Extreme 4x4 roller cam, Thorley Headers, Carter Electric Fuel Pump, Vintage Air, 700r4, 3.73, disc brakes and power steering upgrades.

04-15-2003, 02:22 PM	#5
Blue Beard Registered User Join Date: Jan 2003 Location: Washington State Posts: 8,834	Make sure the right side is also clearing the brake lines. Mine was touching, heating up the brake fluid. __________________ 1970 Chev CST 2003 Harley Fatboy 1975 Chevrolet Step Van 1956 Chev Bel Air 1977 Blazer 2WD For Sale $3000.00 1978 Blazer 2WD For Sale $7000.00 1978 Silverado 2005 Monte Carlo

04-15-2003, 02:25 PM	#6
Yukon Jack Post Whore Join Date: Feb 2000 Location: Rose Hill, KS, USA Posts: 12,684	Clear the brake lines real well as well as the hydraulic clutch setup. __________________ 1970 Blazer with a 400 sbc and 4" lift 1980 Pontiac Trans Am, 455 Oldsmobile 2012 Kawasaki Concours 14

04-15-2003, 09:26 AM	#2
Randy70C-10 Account Suspended Join Date: Mar 2001 Location: Virginia Beach, Va. U.S.A. Posts: 15,320	You should be ok. When you gas the engine, the drivers side will torque "up".

04-15-2003, 03:28 PM	#7
GreenMystChevy Registered User Join Date: Jan 2002 Location: Woodinville, WA Posts: 513	As far as the engine to crossmember clearence, it shouldn't be a problem at all. The engine on my Chevelle sits pretty dang close to the crossmember as well, not quite that close but almost, and that is factory. If you have new motor mounts, I wouldn't think that there would be too much of a problem with the headers, but after time, some settling might take place. I would personally forget about it but I wouldn't want to mess with getting new headers or different mounts. I'd just go with it until you start to see a problem. __________________ Jeremy '71 C-10 '72 GMC K2500 '72 Nova (Dad's) '70 Chevelle SS '55 Sedan Delivery Attempting to build up this here 4x4...make her real tall and purty...well, maybe just tall

04-15-2003, 04:29 PM	#8
breeh Recovering 67-72 Addict Join Date: Oct 2000 Location: North Bend, WA Posts: 1,788	You must have a different pan than I have because I have at least an inch between pan and crossmember. Maybe the later model pan that you have is different somehow. __________________ 68 Short Fleet 4x4; 427; BTO Level 3 700R4; NP205; Dana 60 front and rear; 4" lift with 35's; Disc brakes; AGR variable ratio steering; factory bucket seats; factory tach and tilt. "Friends call me cruzer cuz I like fast cars and fast women"

04-15-2003, 10:00 PM	#9
GMC71k20 Registered User Join Date: Aug 2002 Location: mass Posts: 1,277	hydraulic clutch, are you running a nv4500?

04-16-2003, 09:16 AM	#10
Yukon Jack Post Whore Join Date: Feb 2000 Location: Rose Hill, KS, USA Posts: 12,684	No, a CH465. The donor vehicle (89 1 ton) had a hydraulic clutch that I'm using. Should be pretty sweet. __________________ 1970 Blazer with a 400 sbc and 4" lift 1980 Pontiac Trans Am, 455 Oldsmobile 2012 Kawasaki Concours 14

04-16-2003, 04:18 PM	#11
GMC71k20 Registered User Join Date: Aug 2002 Location: mass Posts: 1,277	should be, considering my clutch squeaks if i even look at it



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