First post here! I've spent a lot of time reading through various threads over the past year since I got my 76 L-48, but never had the need to post.

I'm planning on swapping the stock engine for a crate engine this winter/next spring, and also would like swap the current 4 speed manual to a Tremec TKO 5 speed. Curious if anyone has removed the stock engine and transmission as one unit, and installed the TKO, already assembled to the new engine. My understanding is that the TKO is slightly larger, and wondering if there are any fitment issues when reinstalling.

Lastly, I haven't made a final decision on engine choice. Leaning towards a 383. Not sure if I'm allowed to post links to particular engines from other sites. Not looking to race the car, just wanting something reliable, with some more power than the L-48. If anyone has any suggestions, I would appreciate it!

 

larger engine is usually the way to more power esp if youre not on the throttle. Something with more compression a decent head etc youre far ahead in the long run. The 70s sucked for performance the L48 is nothing more than a station wagon motor with a 4 barrel far as Im concerned. Not worth it.

 

In all the different Vettes and motor/tranny R&R's i have never removed the hood and I never do them attached together.

 

Yes I have installed the engine and tremec tko as a unit, only a couple of weeks ago (you'll have to trust me that the last picture follows the earlier ones, I was a bit busy to take more photos while it was going in). Plenty of adjusting the angle along the way, but it wasn't too difficult, and I still have the fixed manual gearbox crossmember too. Use a trolley jack under the box once it's in the tunnel to adjust the rear and get it over the cross member. Don't forget to stab the tailshaft into the back of the box before it slides home either... My engine's a 383 (388 actually) that I've built myself over the past 6 months. Ugly rocker covers were temporary while dropping it in.

 

Thanks metalhead, exactly what I needed to know.

Any reason you chose to build your engine vs going the crate route? Would you do it again? You don't happen to have a build thread for your car??

 

I just don't trust other peoples workmanship unless I have to... I also got a good deal on an engine from a friend of a friend that, while it ended up needing a complete rebuild, came with a lot of the parts I wanted/needed, which saved a bunch of cash but was more work than working with all new parts. A lot of the cheaper priced crates you just can't buy good components and machining for that cost, which leads me to distrust them, particularly now I've done it myself and know how much time is involved in cleaning and checking everything as you go to get it as good as possible. A crate is probably a sensible option if not planning to do a lot of driving or keep the car for a long time, as they seem to work fine for most people for a few years, but longer term/distance reports I read seemed to show not holding up, leaking or other problems over the long term. Given i plan to keep my car and drive it a LOT (I expect to cover over 10,000 miles a year once I get it sorted), and drive it hard, including track days and other competitive events (I'm currently considering caging it so I can run targa events) I wanted to be sure everything was spot on to work and last for as long as possible. Even just gasket and bolt kits... There's no way that the crate companies can be offering the best gaskets/seals and arp bolts/studs throughout for the price they charge, and most are using hyper pistons, flat tappet cams, and no name heads. This is not to totally bag crates though, they do offer good value for money, particularly for the average 'driven to car shows on sunny Sundays' owner/driver /classic car. That's just not me. I should note that this all opinion, based on here say and internet research, your results may vary!

 

Sorry, missed a couple of q's there. No build thread, though I've posted various parts of it on here (or in my Garage Gallery thread on Garage Journal) in relevant threads. Been slack about maintaining a proper thread though. Yes I would do it again, or, if pushed for time, I would have it built by a local and reputable builder. I'm currently having the Cleveland in my '79 F250 built by a local race engine builder, as it failed and I need it back on the road asap as it's the tow vehicle for my cars and my wife's horses. Having it built as a 393 stroker, 6" forged Chevy rods, forged pistons, mild hydraulic roller and ported 2v heads (it is a tow vehicle after all). Also having it run in on the builders engine dyno, as the f250 is on straight lpg which can cause difficulties bedding in rings. This hurts, I'd prefer to do it myself and it would save me money, but time means that is not an option at this point in time. I didn't consider a crate for the same reasons as above, particularly as this truck does a lot of work and has clocked up over 120,000 miles, much of it with a load, in the 5 years I've owned it.

 

My 1978 started as a L48 / TH350 Auto.

First swap was to a GM Crate ZZ383 with a complete serpentine Kit. (I took the hood off)

https://www.corvetteforum.com/forums...n-my-78-a.html

@2nd swap was a T56 Magnum 6-speed from the TH350 auto. Removed transmission separate from the engine. The problem I see you will have is the lack of a removable transmission cross member. It will make it difficult to do with both connected. ??? I think you may also have problems modifying the cross member without it being removed.

Something to think about at this time is if you what to go hydraulic clutch system vs the Zbar which makes it more difficult to fit headers / exhaust.

https://www.corvetteforum.com/forums...-corvette.html

Running 3.08 Rear end and still gets a 13.18 1/4 ET @ 108 MHP.
27.4 MPH Highway (CDN)

My car is used for track days so reliable engine helps. So far I have had no engine issues with the GM Stock ZZ383. But also remember adding more HP may require you to look at the brakes.

 

Good point on hydraulic vs z bar. I opted to keep the z bar, that meant I could reuse my bell housing and everything else, which made the conversion simple (and cheaper!). If I'd been starting with an auto I probably would have gone hydraulic for similar reasons (easier). But I like the z bar, a nice solid mechanical linkage is easy to adjust and troubleshoot, I just rebuilt each of the joints to get rid of any slop/wear.

I should note that i wouldn't include gm crate engines in my comments above. I'd happily run a gm crate reliability wise, but I think better performance/specs can be gained for the cost if you build it yourself. I'd consider my options if not building it myself though, and would be as happy to run a gm crate instead of having an engine built by a local builder if it looked like a better option.

 

Missed this comment before. As above, no drama installing a tko with engine with the fixed crossmember, wasn't difficult at all. It may be a different story with the t56. The mounts I used (Hurst) just bolt on to the crossmember in a very similar way to the stock 4 speed mount, so no need to modify the crossmember. Swing the engine and box in, with the box sitting on the crossmember, bolt up the engine mounts, then lift the box to get the gearbox mount and bracket in place. Very easy.

Edit: picture added:

 

Go with the above info. If all you need to do is bolt on a bracket.

That's to easy.

 

Sure is!

 

I did engine Remove and Replace for money and my own vette dozens of times. So less time is the goal. The time it takes to dork around R&R ing the hood and lining it all up plus the time of dorking with the load leveler on the engine and tranny combo is not time effective.

It is just not a good idea. The chances of chipping the edges of the hood paint..............

I've changed engines and transmissions at the track and we always did things as fast as possible.

headers are made to clear the Z-bar. Modern clutches made to handle high HP are of minimal foot pedal pressure. Hydro clutches have a vague feeling and it is just one more item to fail.

 

Agreed that you would never remove or reinstall as a pair if you only need to remove engine OR box. However, if both are out and need to go back in, I personally would (and did) install them as a pair, I find it's generally easier to join them out of the car, and it really did go in very easily, without any difficulty. And I might not pull the hood if doing a simple engine pull and reinstall, but as I've been fitting a new engine and box, and it's been in and out several times, and I'm also rewiring, replacing the radiator, and various other work, I pulled the hood. It just makes access much easier. All depends on what job you're tackling at the time. The OP was referring to/asking about replacing engine and box at once, which happens to be exactly what I have been doing in the last couple of weeks.

 

I installed both on my 71bolted together, Stock rebuilt engine and TKO 5 speed. I used SST ( Silver Sport) kit and everything fit perfect.

I had the Radiator Support out - everything lined up perfectly.



Since it's a number matching car I wanted the original drive shaft intact. SST sent a new driveshaft with the kit as well as the mounts and neutral safety, instead of the clutch safety which I did not want.

They also sent the correct shifter handle and shift plate.

For the price and fit of the kit I would use them again.

 

Engine and transmission r&r. Leave the tranny on the ground. Install the engine with bell housing first. Then stab the tranny in



I just did another BBC and 4 speed with the hood on

 

We timed Vette engine and tranny changes. We did a hood off and tranny and engine together. we did a hood on tranny and engine together. We installed the tranny first and tried to stab the engine to the tranny. The by far fastest was the hood not touched and install the engine first and then stab the tranny to it. Manual with the bell housing on the motor for the install. When you have to do this professionally you figure out the best way.


Because of the length of the engine and tranny you have to get the front of the car pretty high off the ground during the install. So it is kind of dorked up for reaching over the fenders to guide it in

 

The 5 speed is a larger transmission, stabbing the trany in I don't think will be that easy. It is not bad with the original 4 speed. I question the 5 speed ? being that easy.. The cross shaft, tranny support is welded in on the stick cars.

Pulling the radiator support makes the install very easy - both ways..

 

The TKO is difficult to get in and out with the engine in (and I had the car on a hoist and using a gearbox jack), I did all my testfitting of box/tailshaft etc that way (with old engine still in the car). Even without a clutch fitted (to make it easier given it was only test fitting) you had to pull the back of the engine down and raise the box and bell in unison but not bolted together to get it all to go into place. Was dead simple to pull the 4 speed out prior... Much less space with the tko. I know people have said it can be done, but it would be very difficult with a clutch as well. And even more difficult without a hoist and gearbox jack... Of course the easy solution would be to make the crossmember removable, but for various reasons some people don't want to do that.

edit: Not sure why you would need the front of the car high off the ground for engine and tranny install? The only reason I had one side of my car lifted was to get the engine crane legs underneath. If it's to angle the engine and box in, that's what a load leveller (initially) and a trolley jack under the gearbox (once it's mostly in, to lift over the crossmember) are for.

 

I have installed engine and trans as one unit and it is not difficult at all. Getting the back end of the car higher than the front helps to create an angle that reduces the amount of adjustment on the load leveler.