coppercutlass

LOL. Its for my friend. Im helping him out with his 68 chevelle. It was good running engine but he felt it was under powered so as we dug in we found it had the double hump heads. Thats a huge plus for keeping the build budget on track. He yanks the heads and it turns out it has the factory LT1 domed pistons but .060 over. IM tyring to get a much info as possible to get this build together properly. WE will no longer be able to run the small chambered heads as compression is over 11 to 1. So we plan on running some 882 casting to get it down to 10.5 to 1 possibly less once we polish the chambers.


My question to you chevy guys out there is what combinations could have been done with the factory pistons and camel hump heads. The pistons seem to be factory forged (trw) just no part number on the piston top like normal which is why i think there are factory .060 over domed pistons. Just a little odd as we dig into the build. Im curious to know what engines came with these heads and pistons as i think its possible we have an lt1 engine ??? Im not a chevy guy and info on the interwebs is a bit misleading and overwhelming

I might add its a mystery becasue my friends father passed away and gave him the car . So all the info is out the window as there is no documentation.

I have not had a chance to measure the bore or pistons or get the crank and block numbers.

The more i dig the more we find things out which is why i gotta go back and get numbers because i had no idea of the factory domed piston until i got home.

orange442

First, check the engine casting #, casting date (both top of bellhousing) and stamped codes on block deck in front of passenger side head, this info. may answer all questions. Also head casting # and date both under valve cover. No LT1 in 68 and no factory .060 over motors. Get all the info and come back and post.

coppercutlass

I know not factory .060 over BUT possibly factory replacement part made by trw is what im curious about since most trw's have the part number on top of the piston and most forged pistons where made by trw for gm for that particular piston .,from what i have seen had no part number on the piston tops like the others did . I know the lt1 was much later but the piston is the same style used for the domed Lt1 piston.

This why im intrigued by this whole thing. Just kind of odd. I havent not messed with an sbc in over 10 years and even then it was all after market stuff. This is pretty cool because its kind of an old school build from what i can see. The pistons are heafty and outdated by today's standards the double hump heads are only valuable to a small group as gm offers much better iron castings such as the vortec heads. My whole role in this build is to make this thing run great .

orange442

1968 was the last year the L79 327 was available. It was 11 to 1 with 2.02 double humps, factory aluminum intake and holley carb. It was rated at 350 hp and was a very strong engine. Not saying your buddies car is an original L79 car, but, if it was, it would be much more valuable than your average 68. Is it a 4 speed or auto? 10 bolt or 12 bolt?

coppercutlass

That's another reason why knowing what I know now i need to dig in a little more. The car it's self has been restored and is cloned to be a 396ss. It had a 12 bolt rear but I don't know what's original and what's not as my friends father restored the car many years ago. I will find out tommorow when I go get the casting numbers.

orange442

The rear axle will have a casting # and date cast on the front of the ribs on the cast center. It should also have stampings on the front of the pass side axle tube close to cast center.