HEI hitting firewall??? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Mechdawg · 03-17-2006, 07:22 PM

Alright everyone Im back with more questions. I finally got the 327 stuffed in between the frame rails but now I seem to have a new issue. The 327 I got has a HEI on it and with the engine sitting in its place the very top back of the wires and cap are all the way against the firewall so should I be looking to pull the HEI out and put a low profile ignition in its place or what? I would like to keep the HEI but dont want to damage anything. What do you all think? If it helps Ill try to post some pics tommarrow.
Thanks
Tim

cdowns · 03-17-2006, 07:25 PM

use hammer make clearance

Longhorn Man · 03-17-2006, 07:27 PM

You could move the engine up to where it should be, but I hear there is a way to turn the HEI to where it won't hit.

rodnok1 · 03-17-2006, 07:30 PM

I think when you use the 6 cyl mounts with v8 you'll have dist fit problems. I know I did. I used a hammer to gain some clearance, but it's hard to make look nice with the engine in. I'm running a Mallory comp9000 now and it's even larger than an HEI.. You can get a small diameter dist from MSD/Mallory.

Mechdawg · 03-17-2006, 07:52 PM

Ok so I take it the V-8's do mount further forward then the inline 6 did? problem is it seems if I did move the engine forward the trans wouldnt sit on its mounts right anymore.

Mechdawg · 03-17-2006, 07:54 PM

Also if I do move it forward do I need to get different tower mounts?

kelsfine69 · 03-17-2006, 07:57 PM

What trans are you running, If its the 3 on the tree you cant move it, its rivited to the frame and its not worth it. If its a automatic get the small block towers and slide the engine and trans ahead and all the bolt holes should line up

jc · 03-17-2006, 07:57 PM

yes, you would need v8 mounts im not sure about the trans but i am curious my self

Mechdawg · 03-17-2006, 08:01 PM

It was a 3 on the tree but its not riveted in it was bolted to the crossmember. The bolt holes line up right now but can the engine be run there or should it be moved forward?

jc · 03-17-2006, 08:12 PM

he meant the cross member is rivited to the frame

Mechdawg · 03-17-2006, 08:22 PM

yeah I thought so I was goina go look but its dark now so Ill have to wait til tommarrow. The only other thing buggin me now is if I do move the motor forward and I cant use the tranny I have then I can get my hands on a saginaw 3 speed but will my drive shaft still fit or will I need to get it lengthened or shortened? Hope Im not buggin anyone you guys have been a great help to me.

Mechdawg · 03-17-2006, 08:26 PM

I also cant seem to find small block engine to frame mounts every place Ive checked has the inline 6 or the big block ones no sbc....

jc · 03-17-2006, 08:31 PM

check with teeitup or biskquik or burnsman on the parts board for the
towers there pretty inexpensive

rodnok1 · 03-17-2006, 08:37 PM

It is easier to just modify the firewall for HEI. Since it is a stick, changing the mounts/clutch setup/diff driveshaft don't justify the move. Lots of people run them with 6 cyl mounts.
On that note, on my '64 I used tall Edelbrock valve covers and they hit horribly bad. I didn't find out until I had everything done and ready to fire it up(used stockers for mock up). I ended up modifying the firewall for clearance, since I had everything else done already.

boogie67 · 03-17-2006, 10:06 PM

I've done this before knock the rivits on the mount out and move it up the holes are there.Evey thing will line up I did this on my dads 67 back in 72.You will have to use the V8 towers.

danny6892002 · 03-17-2006, 11:56 PM

Am having the same problem, my HEI is like 1/2 an inch from the firewall, and i have a 350/350 Auto but if i move the hole engine and trans then i will also need another drive shaft, so i just left the engine the way it is, it good for me. am guessing that that happend because the chassi was for a 6L, i would recommend you to cut a little pice if the firewall and then weld in some thing to cover the hole.

**Green Machine** · 03-18-2006, 12:26 AM

Another thing to check is the rubber cab mounts, especially the front ones. If the mounts are sagging, new ones will give you more clearance near the HEI.

**GMCPaul** · 03-18-2006, 12:39 AM

Green Machine has answered with what is most likely your problem as I've done a dozen or more 6cyl to V8 swaps putting the V8 in the original 6cyl. mounting position and if your cab mounts are good you should have approx. 1" clearance between the distributor cap plug wires & firewall.
GMCPaul

72 Money Pit · 03-18-2006, 12:42 AM

I have the same problem and also will correct it by working the firewall slightly with a hammer. I suggest marking the area where the two or three wires make contact with the firewall. With the cap removed, you will know exactly where to create more clearance. I am also going to take Green Machine's suggestion and check the cab mounts. I don't want to consider relocating the engine because I have the transfer case to also deal with.

**Green Machine** · 03-18-2006, 01:00 AM

BTW - 4wd models all used the "6 cylinder" position whether they were a SB or 6 banger, they were all installed in the rear position.

redneckdds · 03-18-2006, 01:18 AM

mechdawg... check this post, I asked the same thing... you can see where the PO had the motor mounted, it was a v8. The truck was originally a v6

http://67-72chevytrucks.com/vboard/s...d.php?t=192765

stllookn · 03-18-2006, 01:27 AM

I have a V-8 in the 6 hole w/HEI and enough clearance. No firewall hammering here. Listen to GMC Paul and GreenMachine...your cab mounts should be checked and the spacer washers for the front of the cab.

6T8 · 03-18-2006, 01:54 AM

I put a one inch body lift on my Trazer I'm building and have all kinds of room now. It was hitting before. Definitely check front cab mounts. Rick

Mechdawg · 03-18-2006, 12:01 PM

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I have some new energy suspension cab mounts on the truck right now. But I will go out there and check maybe I could raise it up some. Here are a few pics of the progress so far. I did pull the engine and lightly hammered and touched up the firewall. The HEI isnt as bad now but the passenger side valve cover is less then a 1/4 inch away from the firewall.

Mechdawg · 03-18-2006, 12:13 PM

Ok I went out there and measured my front body mount pucks measure right at 1 inch thick. Is this correct? Or did I end up with the wrong set. Can anyone out there give me the correct thickness for the front and rear pucks?
Once again its a 67 2wd short wheel base. Thanks again guys.

03-17-2006, 07:22 PM	#1
Mechdawg Registered User Join Date: Jul 2002 Location: Dover AFB Delaware Posts: 159	HEI hitting firewall??? Alright everyone Im back with more questions. I finally got the 327 stuffed in between the frame rails but now I seem to have a new issue. The 327 I got has a HEI on it and with the engine sitting in its place the very top back of the wires and cap are all the way against the firewall so should I be looking to pull the HEI out and put a low profile ignition in its place or what? I would like to keep the HEI but dont want to damage anything. What do you all think? If it helps Ill try to post some pics tommarrow. Thanks Tim

03-17-2006, 07:25 PM	#2
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	Re: HEI hitting firewall??? use hammer make clearance __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

03-17-2006, 07:27 PM	#3
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: HEI hitting firewall??? You could move the engine up to where it should be, but I hear there is a way to turn the HEI to where it won't hit.

03-17-2006, 07:30 PM	#4
rodnok1 Registered User Join Date: Jun 2003 Location: Linden, North Carolina Posts: 617	Re: HEI hitting firewall??? I think when you use the 6 cyl mounts with v8 you'll have dist fit problems. I know I did. I used a hammer to gain some clearance, but it's hard to make look nice with the engine in. I'm running a Mallory comp9000 now and it's even larger than an HEI.. You can get a small diameter dist from MSD/Mallory. __________________ 64 Panel Rebuild Pics Clutch Replacement and Borg Warner T10 Trans Rebuild 64 Panel 1/2 Ton 350cubes/400hp BorgWarner t-10 3:73 Auburn Posi

03-17-2006, 07:52 PM	#5
Mechdawg Registered User Join Date: Jul 2002 Location: Dover AFB Delaware Posts: 159	Re: HEI hitting firewall??? Ok so I take it the V-8's do mount further forward then the inline 6 did? problem is it seems if I did move the engine forward the trans wouldnt sit on its mounts right anymore.

03-17-2006, 07:54 PM	#6
Mechdawg Registered User Join Date: Jul 2002 Location: Dover AFB Delaware Posts: 159	Re: HEI hitting firewall??? Also if I do move it forward do I need to get different tower mounts?

03-17-2006, 07:57 PM	#7
kelsfine69 18 Till I Die Join Date: Mar 2005 Location: Alberta, Canada Posts: 1,522	Re: HEI hitting firewall??? What trans are you running, If its the 3 on the tree you cant move it, its rivited to the frame and its not worth it. If its a automatic get the small block towers and slide the engine and trans ahead and all the bolt holes should line up __________________ 2011 GMC Acadia 1969 GMC BBC LS7 2007 GMC Crew Duramax 1987 Camaro Iroc 350 Tuned Port Injection 42000Km 1987 Chevrolet Silverado 350 TBI 1987 Chevrolet Silverado 350 TBI(yes 2) Take me drunk, I'm too home...

03-17-2006, 07:57 PM	#8
jc Registered User Join Date: Jan 2001 Location: Jackson, New Jersey Posts: 1,560	Re: HEI hitting firewall??? yes, you would need v8 mounts im not sure about the trans but i am curious my self __________________ 2004 Silverado 2500HD Crewcab 4x4 2000 TOYOTA 4RUNNER 1971 CHEYENNE LWB (THE LOVE SHACK) 1967 c-10 lwb (THE FARMERS DAUGHTER) Last edited by jc; 03-17-2006 at 07:58 PM.

03-17-2006, 08:01 PM	#9
Mechdawg Registered User Join Date: Jul 2002 Location: Dover AFB Delaware Posts: 159	Re: HEI hitting firewall??? It was a 3 on the tree but its not riveted in it was bolted to the crossmember. The bolt holes line up right now but can the engine be run there or should it be moved forward?

03-17-2006, 08:12 PM	#10
jc Registered User Join Date: Jan 2001 Location: Jackson, New Jersey Posts: 1,560	Re: HEI hitting firewall??? he meant the cross member is rivited to the frame __________________ 2004 Silverado 2500HD Crewcab 4x4 2000 TOYOTA 4RUNNER 1971 CHEYENNE LWB (THE LOVE SHACK) 1967 c-10 lwb (THE FARMERS DAUGHTER)

03-17-2006, 08:22 PM	#11
Mechdawg Registered User Join Date: Jul 2002 Location: Dover AFB Delaware Posts: 159	Re: HEI hitting firewall??? yeah I thought so I was goina go look but its dark now so Ill have to wait til tommarrow. The only other thing buggin me now is if I do move the motor forward and I cant use the tranny I have then I can get my hands on a saginaw 3 speed but will my drive shaft still fit or will I need to get it lengthened or shortened? Hope Im not buggin anyone you guys have been a great help to me.

03-17-2006, 08:26 PM	#12
Mechdawg Registered User Join Date: Jul 2002 Location: Dover AFB Delaware Posts: 159	Re: HEI hitting firewall??? I also cant seem to find small block engine to frame mounts every place Ive checked has the inline 6 or the big block ones no sbc....

03-17-2006, 08:31 PM	#13
jc Registered User Join Date: Jan 2001 Location: Jackson, New Jersey Posts: 1,560	Re: HEI hitting firewall??? check with teeitup or biskquik or burnsman on the parts board for the towers there pretty inexpensive __________________ 2004 Silverado 2500HD Crewcab 4x4 2000 TOYOTA 4RUNNER 1971 CHEYENNE LWB (THE LOVE SHACK) 1967 c-10 lwb (THE FARMERS DAUGHTER)

03-17-2006, 08:37 PM	#14
rodnok1 Registered User Join Date: Jun 2003 Location: Linden, North Carolina Posts: 617	Re: HEI hitting firewall??? It is easier to just modify the firewall for HEI. Since it is a stick, changing the mounts/clutch setup/diff driveshaft don't justify the move. Lots of people run them with 6 cyl mounts. On that note, on my '64 I used tall Edelbrock valve covers and they hit horribly bad. I didn't find out until I had everything done and ready to fire it up(used stockers for mock up). I ended up modifying the firewall for clearance, since I had everything else done already. __________________ 64 Panel Rebuild Pics Clutch Replacement and Borg Warner T10 Trans Rebuild 64 Panel 1/2 Ton 350cubes/400hp BorgWarner t-10 3:73 Auburn Posi

03-17-2006, 10:06 PM	#15
boogie67 Registered User Join Date: Mar 2005 Location: waco tx Posts: 584	Re: HEI hitting firewall??? I've done this before knock the rivits on the mount out and move it up the holes are there.Evey thing will line up I did this on my dads 67 back in 72.You will have to use the V8 towers. __________________ 77 swb starting all over again. Last edited by boogie67; 03-17-2006 at 10:09 PM.



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03-17-2006, 11:56 PM	#16
danny6892002 Registered User Join Date: Jan 2006 Location: Texas Posts: 53	Re: HEI hitting firewall??? Am having the same problem, my HEI is like 1/2 an inch from the firewall, and i have a 350/350 Auto but if i move the hole engine and trans then i will also need another drive shaft, so i just left the engine the way it is, it good for me. am guessing that that happend because the chassi was for a 6L, i would recommend you to cut a little pice if the firewall and then weld in some thing to cover the hole.

03-18-2006, 12:26 AM	#17
Green Machine Senior Member Join Date: Jul 2004 Location: Estherville, Iowa Posts: 3,371	Re: HEI hitting firewall??? Another thing to check is the rubber cab mounts, especially the front ones. If the mounts are sagging, new ones will give you more clearance near the HEI. __________________ 1968 C10 307 3spd Long Fleet ------ http://67-72chevytrucks.com/vboard/s...d.php?t=201103 1970 C10 305 Super T10 Long Fleet --- http://67-72chevytrucks.com/vboard/s...d.php?t=202285 1971 C20 383 TH350 Dana Posi ----- http://67-72chevytrucks.com/vboard/s...d.php?t=206894 2001 GMC Sierra 1500 C3 6.0

03-18-2006, 12:39 AM	#18
GMCPaul Senior Member Join Date: Mar 2000 Location: Rockville,In. USA Posts: 3,718	Re: HEI hitting firewall??? Green Machine has answered with what is most likely your problem as I've done a dozen or more 6cyl to V8 swaps putting the V8 in the original 6cyl. mounting position and if your cab mounts are good you should have approx. 1" clearance between the distributor cap plug wires & firewall. GMCPaul __________________ Secure Online Catalog for-GMCPauls Truck Parts Email- GMCPAULS@GMAIL.COM

03-18-2006, 12:42 AM	#19
72 Money Pit Registered User Join Date: Mar 2006 Location: Bountiful, Utah Posts: 9	Re: HEI hitting firewall??? I have the same problem and also will correct it by working the firewall slightly with a hammer. I suggest marking the area where the two or three wires make contact with the firewall. With the cap removed, you will know exactly where to create more clearance. I am also going to take Green Machine's suggestion and check the cab mounts. I don't want to consider relocating the engine because I have the transfer case to also deal with. __________________ 72 Money Pit 1972 Cheyenne K20, crate 290 hp 350, GM HEI, 4 spd, 4:10 w/Detroit Locker in corporate 14-bolt [SIZE="3"]Twice as much invested in it as I could ever hope to get out of it, and still spending![/SIZE]

03-18-2006, 01:00 AM	#20
Green Machine Senior Member Join Date: Jul 2004 Location: Estherville, Iowa Posts: 3,371	Re: HEI hitting firewall??? BTW - 4wd models all used the "6 cylinder" position whether they were a SB or 6 banger, they were all installed in the rear position. __________________ 1968 C10 307 3spd Long Fleet ------ http://67-72chevytrucks.com/vboard/s...d.php?t=201103 1970 C10 305 Super T10 Long Fleet --- http://67-72chevytrucks.com/vboard/s...d.php?t=202285 1971 C20 383 TH350 Dana Posi ----- http://67-72chevytrucks.com/vboard/s...d.php?t=206894 2001 GMC Sierra 1500 C3 6.0

03-18-2006, 01:18 AM	#21
redneckdds Senior Member Join Date: Nov 2005 Location: Queen Creek, AZ Posts: 218	Re: HEI hitting firewall??? mechdawg... check this post, I asked the same thing... you can see where the PO had the motor mounted, it was a v8. The truck was originally a v6 http://67-72chevytrucks.com/vboard/s...d.php?t=192765 __________________ '67/70 Chevy C/10 '10 2500 Crewcab Duramax 4wd Last edited by redneckdds; 03-18-2006 at 02:32 AM. Reason: wanted to add link with pic

03-18-2006, 01:27 AM	#22
stllookn Saving 1 truck at a time! Join Date: Aug 2001 Location: Kent, WA Posts: 6,465	Re: HEI hitting firewall??? I have a V-8 in the 6 hole w/HEI and enough clearance. No firewall hammering here. Listen to GMC Paul and GreenMachine...your cab mounts should be checked and the spacer washers for the front of the cab. __________________ '68 C20 Longhorn 50th Anniversary 400/TH400 '68 C20 Longhorn 50th Anniversary 468/TH400w/buckets '72 C20 Halfhorn (Longhorn w/o cab and front clip) '69 Flxible Cruiser (look up ugly in the dictionary)

03-18-2006, 01:54 AM	#23
6T8 Active Member Join Date: Dec 2004 Location: Tucson, AZ Posts: 233	Re: HEI hitting firewall??? I put a one inch body lift on my Trazer I'm building and have all kinds of room now. It was hitting before. Definitely check front cab mounts. Rick

03-18-2006, 12:01 PM	#24
Mechdawg Registered User Join Date: Jul 2002 Location: Dover AFB Delaware Posts: 159	Re: HEI hitting firewall??? I have some new energy suspension cab mounts on the truck right now. But I will go out there and check maybe I could raise it up some. Here are a few pics of the progress so far. I did pull the engine and lightly hammered and touched up the firewall. The HEI isnt as bad now but the passenger side valve cover is less then a 1/4 inch away from the firewall.

03-18-2006, 12:13 PM	#25
Mechdawg Registered User Join Date: Jul 2002 Location: Dover AFB Delaware Posts: 159	Re: HEI hitting firewall??? Ok I went out there and measured my front body mount pucks measure right at 1 inch thick. Is this correct? Or did I end up with the wrong set. Can anyone out there give me the correct thickness for the front and rear pucks? Once again its a 67 2wd short wheel base. Thanks again guys.

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