1971 K20 LS 5.3L Swap issue headers - The 1947 - Present Chevrolet & GMC Truck Message Board Network

DWilbur · 07-08-2014, 04:04 PM

I have installed my LS 5.3 L in to 1971 K20 4X4 truck and I'm having issue with the headers fitting Dough Throly THY 323. I talked to Dough Thorly tech prior to buying the headers to confirm that they will fit my application. they confirmed they fit. Well they don't even come close. I would like to use headers, does any one know what headers will fit. I have a Dirty Dingo motor mount installed. with 1987 bell housing with hydraulic clutch.

71chevystep4x4 · 07-09-2014, 12:27 AM

Hooker block hugger shorties #2312

DWilbur · 07-09-2014, 12:44 PM

Quote:

Originally Posted by 71chevystep4x4

Hooker block hugger shorties #2312

Thanks for the info. would you by chance have pictures of them installed.

BR3W CITY · 07-09-2014, 12:53 PM

The frame areas look minimal, I'd just clearance out the problem area. I'm not running a manual, but some "massaging" of the mounting ears on the auto's isn't uncommon.

DWilbur · 07-09-2014, 02:05 PM

Quote:

Originally Posted by BR3W CITY

The frame areas look minimal, I'd just clearance out the problem area. I'm not running a manual, but some "massaging" of the mounting ears on the auto's isn't uncommon.

I would have to cut out the hole top flange of the frame for the right and left side. The left side the collector runs right into the hydraulic clutch bracket on the side of the bell housing.

67Steven · 07-12-2014, 11:52 PM

I am running DT headers and I did need to clearance the frame, just a small scallop on each side, but I reinforced the inside area, no problems so far.

DWilbur · 07-17-2014, 07:13 PM

Quote:

Originally Posted by 67Steven

I am running DT headers and I did need to clearance the frame, just a small scallop on each side, but I reinforced the inside area, no problems so far.

I checked out your build thread a couple of time it looks like your engine sits about 1 higher than mine. so the DT headers fit better. your using an auto transmission. I still have problems with the hydraulic clutch bracket that is molded in to the bell housing I would like to use.

DWilbur · 08-23-2014, 07:09 PM

After trying 3 set of headers finally the Headman block huger headers will fit only trimming 1.4" out of the top rail of the frame on each side.

preciador6 · 06-07-2016, 05:35 PM

So it dont matter if i buy DD or Pac fAb im still going to have trouble with headers?

DWilbur · 06-07-2016, 11:02 PM

That's what i found out. I ended up using the Dough Thorley headders and had to modify the 2 front tubes to clear the frame.

07-08-2014, 04:04 PM	#1
DWilbur Registered User Join Date: Aug 2013 Location: San Jose Ca Posts: 965	1971 K20 LS 5.3L Swap issue headers I have installed my LS 5.3 L in to 1971 K20 4X4 truck and I'm having issue with the headers fitting Dough Throly THY 323. I talked to Dough Thorly tech prior to buying the headers to confirm that they will fit my application. they confirmed they fit. Well they don't even come close. I would like to use headers, does any one know what headers will fit. I have a Dirty Dingo motor mount installed. with 1987 bell housing with hydraulic clutch. Attached Images

07-09-2014, 12:53 PM	#4
BR3W CITY meowMEOWmeowMEOW Join Date: Sep 2009 Location: MKE WI Posts: 7,128	Re: 1971 K20 LS 5.3L Swap issue headers The frame areas look minimal, I'd just clearance out the problem area. I'm not running a manual, but some "massaging" of the mounting ears on the auto's isn't uncommon. __________________ *'66 Short Step / SD Tuned / Big Cam LQ4 / Backhalfed /Built 4l80e / #REBUILDEVERYTHING* MY BUILD THE H8RDCPTR //\\ MY YOUTUBE CHANNEL REV J HD

07-12-2014, 11:52 PM	#6
67Steven Registered User Join Date: Mar 2007 Location: Oregon City Posts: 228	Re: 1971 K20 LS 5.3L Swap issue headers I am running DT headers and I did need to clearance the frame, just a small scallop on each side, but I reinforced the inside area, no problems so far. __________________ 1972 Blazer build: http://67-72chevytrucks.com/vboard/s...d.php?t=615744

08-23-2014, 07:09 PM	#8
DWilbur Registered User Join Date: Aug 2013 Location: San Jose Ca Posts: 965	Re: 1971 K20 LS 5.3L Swap issue headers After trying 3 set of headers finally the Headman block huger headers will fit only trimming 1.4" out of the top rail of the frame on each side.

06-07-2016, 05:35 PM	#9
preciador6 Registered User Join Date: Dec 2013 Location: So Cal Posts: 680	Re: 1971 K20 LS 5.3L Swap issue headers So it dont matter if i buy DD or Pac fAb im still going to have trouble with headers?

07-09-2014, 12:27 AM	#2
71chevystep4x4 Registered User Join Date: Sep 2012 Location: Milwaukie OR Posts: 135	Re: 1971 K20 LS 5.3L Swap issue headers Hooker block hugger shorties #2312

06-07-2016, 11:02 PM	#10
DWilbur Registered User Join Date: Aug 2013 Location: San Jose Ca Posts: 965	Re: 1971 K20 LS 5.3L Swap issue headers That's what i found out. I ended up using the Dough Thorley headders and had to modify the 2 front tubes to clear the frame.



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