Big Block Fit

MHROD4 · #1 03-25-2005, 09:40 PM

Help! I am going nuts trying to figure out my problem. To start at the beginning.....
Have a 1969 standard convert I purchased 2 years ago. Had it for 1 month before shipping off for paint, body, etc. It was originally SB, but had BB installed prior to my ownership. Restoration shop lost the original engine frame brackets, but replaced. When I got car back, I noticed the engine was positioned approx. 1" more forward than before (noted seal line on driveshaft yoke, l. header close to ps gear & trans mount struggle). I enjoy the room for work, but here's the problem. I wanted to change from the flex fan that was on engine to the clutch style fan that previous owner removed. It will not fit, due to water pump's proximity to radiator. I've jacked up motor, pulled mounts/brackets & they appear to be the correct parts. The frame brackets are stamped 3950113, &..0114. DOing a Google search indicates them to be NOS GM, however the local dealer can't i.d.
Anyone else have this problem or is there a dimension available, let's say from crank pully to cross member I can get? I now suspect the car came to me with the SB frame mounts as the heater case was hammered up pretty good to accomodate the valve cover.

Thanks!

Mark H

MagicRat · #2 03-25-2005, 09:49 PM

I am not too swift on the BB but I do recall the SB and BB engine mounts were interchangeable, but different, so you are probably on the right track.

I also recall there were factory short and long waterpumps. Maybe you have the long one. I expect you would need the corresponding short pully as well.

Those flex fans are real power suckers. What about an aftermarket electric fan, for greater efficiency?

MHROD4 · #3 03-26-2005, 11:02 AM

Thanks. Yea, actually I've taken pump dimensions & will go shopping to see if any stores have the short version as well as a new pulley. Only other problem I will still have is the lack of room from the L. header to p/s gear. I want to install a set of ceramic headers while I've got it all apart, but don't want to fracture the coating if it doesn't fit.

Thanks again.

molhannah · #4 03-26-2005, 06:38 PM

Aren't there more than one set of hole in the frame for positioning the motor mounts? I know all the frames GM made are the same whether a sm or bb car only difference is the springs for the weight. If your motor isn't where it use to be with the mark on the drive shaft and the clearance you had, I would look at another big block set up and compare the mounts and position before you spend anymore money on parts that might not work in the long run.

MHROD4 · #5 03-26-2005, 11:52 PM

Unfortunately, there is just one set of holes in the crossmember. I visited a neighbor who is doing a '69 Firebird & the frame member is the same, but totally different mounts for the pontiac block.
The more I think about this, I'm convinced the previous owner had used the small block frame mounts, as Classic Ind. notes the use of the new mounts to move the engine up & lower right side (for eng. torque). My cowl induction a/c is pretty well centered in the hood hole. The short water pump will not work as it does not have the proper holes for alt. & p/s brackets. Thinking about following Magicrat's suggestion on the elec. fan setup....
Thanks,

Triplet · #6 03-27-2005, 09:25 AM

You're right on. The BB motor mount brackets are1/2"-1" more towards the rear of the car than the SB brackets. I've been through the same thing. I had the same interferance with the steering shaft too. The BB brackets are pretty hard to find, but the small block ones seem to be everywhere and I think are also reproduced. If you change back to the BB brackets, all will be right in the world! Good luck,

MHROD4 · #7 03-27-2005, 08:31 PM

Quote:

Originally Posted by MHROD4

Unfortunately, there is just one set of holes in the crossmember. I visited a neighbor who is doing a '69 Firebird & the frame member is the same, but totally different mounts for the pontiac block.
The more I think about this, I'm convinced the previous owner had used the small block frame mounts, as Classic Ind. notes the use of the new mounts to move the engine up & lower right side (for eng. torque). My cowl induction a/c is pretty well centered in the hood hole. The short water pump will not work as it does not have the proper holes for alt. & p/s brackets. Thinking about following Magicrat's suggestion on the elec. fan setup....
Thanks,

Are you sure the bb mounts are 1/2-1" back farther than the sb?? According to Classic Ind. tips, they pull engine forward from the sb version. Here is their link explaining. http://www.classicindustries.com/tips/tip016.htm

Thanks. I think I'm getting closer

Triplet · #8 03-27-2005, 10:54 PM

You got me thinking. I went out to check my headers, and I was thinking about my steering shaft and the actual header interferance area, and you or Classic industries are right. It actually moves the motor to the front of the car 1/2 to 1", I was backwards in my thinking on how I remembered the headers interfering with the steering. I thought the headers were moved back by the BB mounts so that they fit, but they actually moved the engine forward. Sorry about that, gald you cought it though. But, as you ARE finding out, there is a difference. I couldn't find anyone who knew that. Everybody just told me that they were the same. Good luck, and sorry about the confusion!

molhannah · #9 03-27-2005, 11:58 PM

Hey guys lets go back to his original statment; I have a 69 standard convert. The classic industries parts are for a Nova or Camero. If you look at the Yearone site it shows all v8 1968-1972 Chevelle models except 307 and 1970-1972 Monte Carlo use the same frame mounts and a different engine mount for just the big block. If I was you MHROD4 I would just call there 1-800-yearone and talk to a tech. It's free and you will know for sure.

MHROD4 · #10 03-30-2005, 07:58 PM

Hey All:

Just wanted to let you know the latest. Called Year One & confirmed the engine brackets I have are correct (p/n's referenced prior matched samples pulled while on phone). Tech also said '69 396 most likely came with fixed fan, not clutch. Found a nice source of info on 1st gen. cooling options here --> http://www.camaros.org/coolingsystems.shtml
Site indicates 3 different clutch configs. dependant on clearance needed.
My car being originally small block w/a/c, had the clutch I received when I purchased car. Bottom line, I am losing the clutch fan, will install current flex fan for the moment, but will save my dimes & get a pair of electric fans, hook 'em up to a thermal switch setup & be done with it. Still aprehensive about the ceramic header clearance when they arrive, but who knows, I still have a come-a-long to "adjust" engine position if needed...

Thanks for the comments - Happy motoring "rubber side down"

POST REPLY TO THIS THREAD