Well, ran into a problem

[Yukon Jack]

As many of you know, I am in the middle of a big project that started out with swapping out my 307 small block for a big block. All was going seemingly well. Was tackling the big block fitment issues with a 2" body lift. My truck has been at the paint shop for a while and this weekend they started placing the body on the frame only to find out that I still have a big problem with the engine hitting the firewall. More than likely I will deal with this problem by moving the engine forward about 1 1/2". The bright side is the paint on the truck is looking great and it will all be worth it in the end.

My other two options are to cut and modify the firewall or add a larger body lift. Don't really want to do either of those options but I haven't made up my mind completely yet.

[Bram]

Man that really stinks! How many inches forward do you have it right now?

[Yukon Jack]

The engine is in the facotry small block location. From my research it sure looked like I could leave it there if I did the body lift. Nope!

[Tennman]

Looking good man ! Haven't talk to ya in awhile,but i been watching ! I had the same problem. After a 3 inch body lift and a little pecking on the passengers side everything was fine. Aslo got to use the GM electrionic dist. and you know how big they are. I was afraid of moving my engine forward ! Didn't know how it might drive or handle on the highway. I know an airplane flys funny when you get too much weight forward or aft. If you move it forward i'll be curious to know just how it drives,so i'll still be watching for your post man ! Your looking good though man !

[Tennman]

By the way,i'll take your project off your hands if your getting tired or bored of it ! *LOL* Besides,with gas prices going up and up.........your probably won't be able to drive it anyways ?!?!

[Yukon Jack]

Tennman, so how much did you have to massage the firewall? Your engine was in the small block location, right? We are using the same valve covers so that is good to know you were able to get them to fit. I would be inclined to change from a 2" to a 3" body lift if that would correct the problem I am having, rather than fight moving the engine forward. I sure don't want to do a body lift any bigger than that though.

[JIMs70GMC]

Looking good!

[Faster_than_you]

you know I have heard on the boards some one else had to move there bb forward a couple of inches also. You dont want that new pretty paint job messed up now.

[454_72_4X4]

Hey Yukon,
I couldn't see you r pics but I have a BB in my 72 on the stock SB mounts and I have some pics of my firewall mods.
I just got the new motor in mine a few days ago and am currently waiting on an intake so I can finish it and fire it.
I have no body lift though and more than likely different valve covers also.
Just a personal thing but I'd never move a BB forward unless there's absolutly no other choice. Especially if your still running a 44 or 10 bolt front end.

The board changed so I'm not sure how to post pics now but this is the right side of the firewall if the pic works.


I'll dig around and find the pic of the left side if this one works.

[454_72_4X4]

Well I don't know if anybody else can see my pic but I can so here's the left side.



Both sides could be done considerably better looking by someone with more skill!

The right side turned out pretty good but the left is ugly.
I just used a ball peen hammer on the right side and started tapping until I got a fairly nice round "dent". The left side was a little more complicated cause of the clutch rod and the gas pedal mount. Don't laugh at my clutch rod boot and retainer! LOL!!

BTW, now I can see your pics Yukon. VERY nice. I see one major change I'd make to your truck though. That change would be the location, I think it would look a lot better in MO than it does in Kansas!! Hahahaha

[Yukon Jack]

Thanks for the pics. Is the engine installed now - if so, can you post some pics of it. Thanks!

[454_72_4X4]

Yup, it's in there.
This is the only pic I have of it right now but I can take some more. No problem.

This one doesn't show much in detail though.



Any specific areas you want to see?

[Yukon Jack]

If it is simple to get more pics, a close up of the area of each valve cover next to the firewall to see what type of clearance you got.

Did you have to clearance at all for the block or just the valve covers?

[454_72_4X4]

I'll see if I can get some pics later today that show it better.
I can't remember if it's just the valve covers or the head also.
I did the "clearancing" about 5 years ago or so.
The only reason it's apart and I have the pics now is cause I swapping from the old 396 to the 454 and I just decided to take some pics while I was at it.

I can tell you it has virtually no clearance on the left side though. I had to replace the taillight wiring harness a couple of years ago and had to use a screwdriver to pry the firewall back slightly to make room to slide the wires between the valvecover and the firewall! I'd guess it at 1/8 in. or less.
It's that tight but it doesn't rub. Hell, I like 'em tight! LOL!!
The motor is tied down solid too though.

I also run an HEI ignitionand can pull the distributor out with no mods to the firewall in that area. It's really tight too though.

[smitty62]

Contrary to what would seem logical--BB's are not that much heavier than a SB-At one time, I knew just how much, but I've forgotten. I doubt moving it forward an inch or so would hurt anything. Just my 2 pennies worth.

[Mixup]

These are not exact weights but a small block is about 575lbs and a bigblock is about 675lbs. It depends on the year of the motor and if it has aluminum intake and heads etc.

[Palf70Step]

I'm going to be the dummy here. Didn't the trucks come with BB from the factory? Or was BB just for 2wd?

Even though you got it painted, I think I would massage the firewall Yukon. With all the other mods you had to deal with on exhaust and all, I don't think those area's would interfer with your heater to get you clearance. I wouldn't lift it higher personally. I don't think they look that good with higher body lufts.

My $.02

Good luck with whatever way you decide to go!!

[crazy longhorn]

Well, everybody knows that my favorite things to do is stuff an eng as tight to the firewall......then lite the torch! in your case, with fresh paint & as pretty as it is, i would opt to slide the eng ahead for clearance. you will have to deal with the driveline issues, clutch Z bar position, & exhaust, ect....but what the he!!, its just a little money & time. that truck is lookin good crazyL

[breeh]

Yukon, As many others have expressed their opinion I am going to give you mine. I think that the only correct way to do this install is to move the BB forward 2". I noticed absolutely no ill effects on the handling when I did this. The benefits are that 1) you don't have to beat up your cab, 2) you can get your HEI cap off no problem, 3) if gives you a little more room underneath to hook the exhaust up to those headers, 4) the motor is now exactly where it needs to be to use a factory BB 2wd fan shroud, and 5) I didn't want a body lift and I didn't need one since I moved the engine forward.

BTW, your truck looks great. I can't wait to see it completed!

[454_72_4X4]

I think that the only correct way to do this install is to move the BB forward 2".

I'm gonna have to argue with you on that breeh.
The only "correct" way to fix it is to put a small block back in it. Since these trucks never came with a BB in them it's always going to be a custom job to put one in and there's no "correct" way to do a custom job. There's just "different" ways to go about getting it done.

Either way has it's pro's and con's.

1) you don't have to beat up your cab, 2) you can get your HEI cap off no problem, 3) if gives you a little more room underneath to hook the exhaust up to those headers, 4) the motor is now exactly where it needs to be to use a factory BB 2wd fan shroud, and 5) I didn't want a body lift and I didn't need one since I moved the engine forward.

1. Quite true. Can't argue with that!
2. My cap comes off just fine.
3. True again
4. and 5. I don't care for body lifts myself but he has one so the shroud is probably going to have to be another custom job. I used one from a late 70's to early 80's Monte Carlo with the "big" radiator and a whole lot of timming and fitting but it fits great now. But then I'm running a Griffen aluminum radiator too.

6. Just to add my .02 again. Front end weight. Trucks need all the help they can get when it comes to that. Move the motor forward, add a heavy bumper, and possibly a winch and thats a bunch of extra weight up there.

All the specs I've every read put the BB about 200lbs. heavier than a SB.

[smitty62]

These trucks didn't come with a BB???? Now I am confused!!! Also, there is no way the BB weighs 200# more than a SB!

[crazy longhorn]

The 4 x4s didnt come with a BB ....in fact, the sb was set in i 6 position(as compaired to a 2 wd truck). for what its worth, Ill bet that that custom flatbed on the back will "counter " any extra weight from moving the BB foward Remember guys.....this is the NUT of eng setback talking! i just dont think this app would have a problem with the eng foward(& its too damn pretty to cut or bend) best of luck,crazyL

[breeh]

454_72_4x4, points well taken. The intent of my message was to say exactly what you said:

Since these trucks never came with a BB in them it's always going to be a custom job to put one in and there's no "correct" way to do a custom job. There's just "different" ways to go about getting it done.

BTW, nice job on the mechanical clutch fab! I wussed out and put in an automatic to bypass that whole issue. Yukon used a hydraulic clutch which I think is a brilliant way to go about it.

[Pont]

Breeh, you did wusse out by putting an automatic in it! J/K

I'm still running the stock bellcrank (z-bar) clutch rod in mine and my BB is sitting in the SB location. No room for an HEI so I went with Mallory Unilite. Low-Pro valve covers and everything clears but it's very very snug. No body lift on mine, I refuse to run one. I would rather move everything forward!

[454_72_4X4]

nice job on the mechanical clutch fab!

Thanks!
There's some other updated pics of it floating around here somewhere. I think in the 4X4 forum.
I can't take the credit for it though, I copied it from another guy that I know.

I'm glad you didn't take my comment as a flame or whatever. I wasn't intending it that way.

Another consideration is the shifter. I have no problem with cutting a new hole or making the factory one bigger but some people might. Hell, I cut out the hole for the tranfer case shifter and moved it to the left side just so I could bend the factory shifter closer to me.

I got the pics of the firewall Yukon. I just have to upload them to imagestation so I can post them.