I'm still looking for other 1973 LS4 454 owners to help me answer the 2 or 4 bolt main cap question. I've got an original 4 bolt main in my car and it seems to be one of a few. Anyone else ever come across one before... let me know.
Thanks,
Wedge

Are Glen and I the only 73 454 owners out there? The black book says there were 4400 made in 1973. I mean, I know I sometimes drive mine fast... but did all the others get totaled? If anyone out there even knows someone with a 73 Chevelle SS, El Camino SS or a Monte Carlo SS, please get them to respond here. This is truly a perplexing situation. Lee Willis has helped by verifying some numbers of production, and anything helps.
Thanks,
Wedge

Hi, new guy here. have a 73/454,,, dont know if I have a 4 bolt. Haven't opened it up yet. maybe over the winter I'll get in there (new owner/ spent the summer driving it). there was a recent post on another forum about this. theres supposed to be a telltail sign in the 3 bolt hole sizes above the oil filter,. dont have the forum/site remembered, will try and find it for you. apparently your not the only one with a 4 bolt main.
think I remember it was the blocks used in the earlier productions of 73 that had a chance of being 4 bolt.

never mind wedge,,,, it was "YOUR" post I remember'd reading about the bolt sizes. I should be able to check my engine this weekend. My vin #'s 408500's , so doubt my engine in the 8000 production range would be 4 bolt

I'm finding out that it's based more the luck of the draw, not when the car left the assembly line. I guess these were "returned" blocks that did not get used in the racing program. Rather than scrap them out, they built them up as production LS4's to get rid of them. I still have to drop the tank on mine to read the tank sticker. One GM therory is that mine had been ordered with the ZO7 off road package. I'll let you know.
Wedge

maybe, (with luck) you've got one of their prototype engines called the LJ-2. It was a 454 , 460 H.P..Modeled after the 427 High per.
They put that together in 1973, never put into production during the gas crises stuff & government laws.
I think the LJ-2 was supposed to be solid lifter, Have no other info on it

See...thats why I like this place so much! Thats one I've never heard of. This engine has all the correct stamping and casting codes as a standard LS4, and it does have hyd. lifters. If I can actually get off my ass... (and take a day off from the slopes), I'm gonna drop the tank. I really don't think this is anything special... not like an L88 tanker... it's just odd. I've been told by Mike Vietro at Corvette Mikes it would be more rare if it actually was a Z07 option. Only 45 of those left the factory. He says that would be better because it is verifiable, whereas a 4 bolt could be just an oddity of production. Either way its still strange... I'm just looking for more. Let me know what you have.
Wedge

I have rebuilt some 454's in the past. I have rebuilt some 454 LS/5's & LS/6's from 1970-1973 units.
As regard to a 454 LS/7,460HP (for the 1970 vette),I understand that only one was built (never sold) for testing at
GM. These units were never RPO'ed by GM that I know of.

Hi...
Been gone for a while putting some miles on the car. Short season here in Montana... gotta get it while the gettin's good. Thanks for all the posts... heres what I have been able to come up with. The car is a late production LS4, near to the end of the run for the year. According to a person in the GM "front office", 12-20 LS4 4 bolt blocks cast especially for the racing program were used to complete orders for the 73 build year. These engines did indeed go into 3 other gm models.
I pulled the tank this year... but the sticker was too degraded to be of any help. Also, when I purchased the vehicle in 1984, no other records were available. This is a high optioned car, but all I could read on the tank sticker was a front license plate mount and AM/FM stereo radio. I was at least hoping to get a destination code.
So... if anyone in here knows how to retreive info of past owners, the original lot it was shipped to, anything... based on the vin #, please let me know.
Thanks,
Wedge

Not a vette but a 1973 Chevelle Malibu with #s matching LS4 drivetrain.

http://www.gearheadmex.com/images/pic017.jpg

Just purchased the car and do not physically have the car home yet but I am quite certain this was a 2 bolt main engine.

More pics and info on my homepage.www.gearheadmex.com (http://www.gearheadmex.com)

Paul

Man... I thought this post was buried in the back 40 with all my ex's. Thanks for finding it!
I wish my tank sticker looked that good. Thats a freakin novel compared to mine. You can identify a 4 bolt 3999289 block from the outside without removing the oil pan. On the oil filter boss there are 3 plugs that cap of passages for external oil coolers. A 2 bolt has a 5/16, 3/8 and 1/2 front to back in that order. A 4 bolt has 1/2 and 1/2 and 3/8. There was a good picture of the 2 bolt pattern in Glens reply to my original post titled 73 LS4 from 2005 in C3 forum. If you can't find it let me know, I'll copy some pictures and post them. Let me know what you find out.
Wedge

Thanks for the info on the oil passage bolts,
now I shouldn't have to pull my pan. :)