UUGGHGHHH....I dropped my big block 454 into my 72 Chevelle today and everything was going fine. Hooked up the Tranny, tightened up the motor mounts, then went to connect the converter to the Flexplate......womp womp womp. The flexplate holes are about 1/2 inch lower then the holes on the converter. I went and looked at my TCI Flexplate I had on my SB 350 and low and behold it had 2 sets of bolt hole. 1 set was about 1 1/4 inch off the teeth and the other was 1 3/4 off the teeth. The factory flexplate on the 454 had ALL it's holes drilled to the 1 1/4 holes. Oh well...live and learn. I knew I couldn't use my TCI Flexplate from my small block because it was internally balanced and the 454 is externally balanced but I didn't know there are 2 sets of bolt holes. So out comes the engine tomorrow...again...so I can take off the flexplate and get a new one with the correct holes.

Lesson...always measure EVERYTHING before proceeding. GEESH


Jacen

Yup, that's about it.

you just learned a lesson, lol-all you need to do is unbolt the trans, slide it back a little, unbolt the flywheel, put in a new "dual" patter ext. bal. one(make sure your bolts are the size of the holes), should have just enough room to get a torq wrench in there-i have done that a few times

you just learned a lesson, lol-all you need to do is unbolt the trans, slide it back a little, unbolt the flywheel, put in a new "dual" patter ext. bal. one(make sure your bolts are the size of the holes), should have just enough room to get a torq wrench in there-i have done that a few times

I had the same problem several years ago when I swapped converters and did exactly as forcd ind states...not a big deal and no need to pull the motor.

Tip: Replace a couple of bell housing bolts (one on each side) with a 3/8 x 4" bolts. When sliding the trans back these bolts keep the front of the trans from dropping and aid in mating the trans back to the motor.

Tip: Replace a couple of bell housing bolts (one on each side) with a 3/8 x 4" bolts. When sliding the trans back these bolts keep the front of the trans from dropping and aid in mating the trans back to the motor.

Now that's about the most frickin brilliant idea I've heard in a long time...:beers:

I redrilled my flexplate using the torque converter as a guide. There was lots of room for the new holes. I would think that as long as the converter bolts don't bind against the flexplate you're fine.

I did this same exact thing just earlier this summer..........

It was nearing the end of the day, and putting these bolts in was the last thing I was going to do then call it a day. Things had gone *so* well that day, I should have known something was going to kill the mood! :)

We did end up pulling the engine back out, installing the new flexplate, and shoving it back in there. But - in the end - it was more than worth it. The stock BB in there now has more torque than that car has ever had.

I ran into that when I first dropped the 454 into my chevelle. I just grabbed a die grinder and elongated a set of holes about 1/4 inch. Never had a problem. I actually had to reuse the same flexplate in my el camino. but the new converter had holes for both the larger bolt pattern and the smaller bolt pattern. jim

I ran into that when I first dropped the 454 into my chevelle. I just grabbed a die grinder and elongated a set of holes about 1/4 inch. Never had a problem. I actually had to reuse the same flex plate in my el camino. but the new converter had holes for both the larger bolt pattern and the smaller bolt pattern. jimSo you turned the round holes in the flex plate into slotted holes? I dunno, but that sounds to me like a recipe for something bad to happen. Especially if it's in a higher horsepower application. I mean no disrespect here, but I'd be hesitant to do something like that. I mean, all the torque from the engine is placed on the bolts that go through those holes, correct? So by elongating those holes with a die grinder and burr tool, aren't you inviting lateral movement and therefore additional stress to be placed upon the transmission input shaft? I sure would think so.

I guess Im your old school shade tree mechanic without the tree. But my reasoning is the torque converter is centered up into the crank by the hub going into the back of the crank. The converter bolts basically just clamps the converter to the flexplate, Im not sure but are the holes exactly 3/8 of a inch or is there wiggle room in the converter holes or the flexplate holes? If theres wiggle room, elongating it just give is more wiggle room. Ive seen converter bolts loosen on cars and wallow out the holes, everyone that ive ever seen or heard about, the guy usually just retightens the bolts and never had a failure. I ran it like that for over a year, ended up swapping to a muncie, but the flexplate is in my elcamino now. jim

I guess Im your old school shade tree mechanic without the tree. But my reasoning is the torque converter is centered up into the crank by the hub going into the back of the crank. The converter bolts basically just clamps the converter to the flexplate Jim, I'm not a pro auto mechanic myself either, and there are some things I miss occasionally and fail to understand too. Not trying to pick an argument with you. Atleast you've replied to my last set of comments on this. I can respect that.

For the sake of others who will read this thread, I'll just add that although I've only installed a transmission and a torque converter and flexplate once (which was recently on my present Chevelle project) I don't remember anything that centers the torque converter in the front, other than the 3 bolts that pass through it's feet and through the flexplate (some competition models having 6 feet and using 6 bolts like the one I installed). And in the rear of the converter, it's ofcourse centered by the splines of the transmission input shaft that it rides on. I know that the flexplate is centered onto the back of the crankshaft, but I didn't think that the torque converter is too. Atleast that's the way I remember it. I'd have to remove the flexplate dust cover to verify that. that's a good question you pose. maybe you're correct, I dunno. I'll need to check that out.

Billy
The torque converter is centered by the snout on the front of the converter fitting into the recessed area of the crank.

http://www.procarcare.com/images/shar/encyclopedia/8852KG05.gif

Billy
The torque converter is centered by the snout on the front of the converter fitting into the recessed area of the crank.Dan & Jim, thanks for the correction on that (now don't I feel dumb:D). Sorry Jim. :thumbsup:

Kinda makes me wonder why they don't just make flexplates that have slots for the bolts instead of holes. I know that some of them are "dual pattern" having 6 bolt holes in them (3 wide pattern, and 3 narrow) but why not just 3 slotted holes? Well, there I go again being analytical. Don't mind me. :noway: