Engine Set too far back

[elorenzof]

I am replacing an engine in a 68 c10. It currently has a 350 small block with a "4 on the floor". R, 1, 2 and 3. It originally had a straight six.

For the customer, i am to replace the engine with a rebuilt small block. The old small block used to have a non HEI distributor, and due to the trans mounting, (still factory mounting with the trans crossmember still riveted to the frame) the smaller distributor's cap was only about 1/4 inch away from the firewall. (toward the back of the distributor cap, the spark plug wires rubbed on the firewall.

Because it HAD a straight six, I'm assuming the trans was set back further? as the engine in it now that i pulled out was not only super close to the firewall, but was also tipped back at an angle with the front of the engine way higher than the back. After pulling the motor out, i noticed that the engine perches are further back than a normal small block perch, and the bottom bolt of the perches were not bolted down, but just resting on the center of the front crossmember as whomever replaced the straight six didnt bother to drill and bolt down the perches.

I need this engine to be set forward. for many reasons. To make it properly set and for distributor clearance. What do i do? I can pull and replace engines all day, but i need some advise. The 4 on the floor standard trans does not have one trans mount in the center of the trans like a th350 and 400 but has two mounts one on the left and one on the right.

Do i: pull the trans, un-rivet the transmission crossmember, move it forward, and set the engine and trans properly and extend the driveline? if so, what about the linkage for the clutch? how do i keep it aligned properly? moivng the trans forward will change the projection and orientation of the clutch z bar mount on the engine not to mention with it moved forward the clutch mounting on the frame will still be in the original place and not align either.

Im sure someone else has been thru this, i just need some direction.

Thank you!!

Lorenzo

[LockDoc]

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Yes, you will have to remove the I6 cross member. The I6 and v8 cross members are different, that is why the engine angle is wrong. The perches are also different.

I posted some pictures in this thread:

https://67-72chevytrucks.com/vboard/...d.php?t=706423

Edit: Here is a thread I posted about the differences in the frame brackets/perches.

http://67-72chevytrucks.com/vboard/s...d.php?t=732393

LockDoc

[Furno68C20]

Originally Posted by elorenzof

I am replacing an engine in a 68 c10. It currently has a 350 small block with a "4 on the floor". R, 1, 2 and 3. It originally had a straight six.

For the customer, i am to replace the engine with a rebuilt small block. The old small block used to have a non HEI distributor, and due to the trans mounting, (still factory mounting with the trans crossmember still riveted to the frame) the smaller distributor's cap was only about 1/4 inch away from the firewall. (toward the back of the distributor cap, the spark plug wires rubbed on the firewall.

Because it HAD a straight six, I'm assuming the trans was set back further? as the engine in it now that i pulled out was not only super close to the firewall, but was also tipped back at an angle with the front of the engine way higher than the back. After pulling the motor out, i noticed that the engine perches are further back than a normal small block perch, and the bottom bolt of the perches were not bolted down, but just resting on the center of the front crossmember as whomever replaced the straight six didnt bother to drill and bolt down the perches.

I need this engine to be set forward. for many reasons. To make it properly set and for distributor clearance. What do i do? I can pull and replace engines all day, but i need some advise. The 4 on the floor standard trans does not have one trans mount in the center of the trans like a th350 and 400 but has two mounts one on the left and one on the right.

Do i: pull the trans, un-rivet the transmission crossmember, move it forward, and set the engine and trans properly and extend the driveline? if so, what about the linkage for the clutch? how do i keep it aligned properly? moivng the trans forward will change the projection and orientation of the clutch z bar mount on the engine not to mention with it moved forward the clutch mounting on the frame will still be in the original place and not align either.

Im sure someone else has been thru this, i just need some direction.

Thank you!!

Lorenzo

You should have enough room to get a HEI distributor cap installed with the SBC in the rear position (i6 position). I have a 283/ sm420 in the i6 position with a new HEI. It’s tight but it saves having to replace the driveshaft and trans crossmember.
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[geezer#99]

Or just get a small cap hei that is the same size.

Some on here.




https://performancedistributors.com/

[Joyridin]

Originally Posted by LockDoc

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Yes, you will have to remove the I6 cross member. The I6 and v8 cross members are different, that is why the engine angle is wrong. The perches are also different.

I posted some pictures in this thread:

https://67-72chevytrucks.com/vboard/...d.php?t=706423

Edit: Here is a thread I posted about the differences in the frame brackets/perches.

http://67-72chevytrucks.com/vboard/s...d.php?t=732393

LockDoc

Thanks for those perch mounts pics! No wonder the BBC somebody hacked in my truck didn't fit right. I also didn't realize the 292 and 250 mounts were so different.

[LockDoc]

Originally Posted by Joyridin

Thanks for those perch mounts pics! No wonder the BBC somebody hacked in my truck didn't fit right. I also didn't realize the 292 and 250 mounts were so different.

No problem.

On the 292, actually only one side of the 292 brackets are different. The drivers side is the same as the 250. The passengers side is one of a kind.....

LockDoc

[elorenzof]

As a reference, here is the engine minus the radiator upper and lower and hoses as it sat before we removed it from the truck. @LocDoc, thank you for your response,

What would you do? The engine can't stay like this. The customer wants to stay manual trans. Even if i was to move the trans crossmember forward, it is already sitting on the upswing of the frame from the cab to the engine bay, moving it forward will raise the trans, and then the cluch will not be in align for the z bar to sit properly and probably wont work. is there a different clutch linkage solve that (clutch linkage) problem?

I cant even tell you what type/model/make this transmission is. it has a rectangle 6 bolt plate on both driver and passenger sides and is relatively short.

[Grumpy old man]

Looks like someone just dropped a V8 in using the original 6 engine perches. Look at the vin if it starts with CS it's a 6 manual trans cross member (because it's still rivited in ) CE would be the V8 trans cross member . To move the engine forward you need a set of V8 engine perches and a V8 manual trans cross member . Doing this means the trans will move forward about 3" also so the shifter will move 3" forward and a new driveshaft . It's a lot of work with the cab in the way . You may want to consider other transmissions / bell housings , I swapped my 67 short bed 6 truck and used all the stock V8 parts to put a V8 in the stock location it's not cheap . here is a couple pictures of the V8 perches and a V8 manual trans cross member on the left and a 6 manual trans cross member on the right .

[Grumpy old man]

This picture shows the V8 cross member sits further forward in the frame I used the 67 stock bell housing and a Muncie M-22 trans .

[tim_mc]

There are lots of SBCs in the i6/4x4 SBC rearward position, mine included. Hopefully with the correct mounts and crossmember everything will align correctly and you won't need to lengthen the driveshaft or mess with the clutch linkage. My '67 frame was already set up for an SBC in the rear location, so I kept it there to avoid the costs to move it like Grumpy mentioned. My HEI is close to the firewall, but still clears OK. I can remove the cap with no issues. I used a 4x4 SBC radiator shroud to fill the gap.

[Indyuke]

OP, it appears you have the SM465 transmission.

My 68 came from the factory with the 307 SBC and the SM465 trans. I'll see if I can get some pics of the clutch linkage that you can take a look at.

Somewhere on here is a thread that goes into detail about the difference between the I6 and V8 clutch linkages... maybe someone can link it.

Edit: 2nd page on this thread. Post 33 shows the correct clutch parts you'll need for the V8. Post 34 shows a clear shot of "a" v8 clutch linkage, including the location of the frame bracket and the V8 z-bar bracket. The reason I call it "a" V8 bracket, is because even though everything appears to be in the correct location, the picture shows the use of an I6 frame bracket and z-bar instead of the correct V8 frame bracket and z-bar.

[Jason Banks]

The best thing you could do is get the motor perches, transmission crossmember, clutch linkage, driveshaft and transmission hump from a V8 donor truck.

I think that may be the most expensive thing you could do though.

Cheaper solution might be some other type of electronic ignition with a smaller distributor cap.

[Palf70Step]

I have had 2 trucks with V8's in the 6 banger position. HEI fits, tight, but no issues. However, you cannot pull or put engine in with the cap on. I normally left distributor out, dropped in engine, then dropped distributor in, set it up, then added rotor and cap.