283 Nova Block Questions

[Kingpen]

I have a cast#721 Nova Block that is Std. 283 .Ive heard old tales of the Nova blocks being really thick & that G.M. used some of the same blocks for 283 & 327.Guess that would be why the 283 block would have extra material in the cylinder walls...Also,alot of the books & what not list this block as a 283 and some list it as a 327,depending on year model.this one has a December '63 cast date meaning '64 year model......it also has 721 cast under the timing cover(same as back of block) but also has 870 under the timing cover too.I know the early 327 blocks had a cast # of "870" because I have a few in shop...was this 870# along with 721# mean it was used for 283 & 327?......I know alot of 283 Stock & S/S guys use this block instead of a bowtie because of cost---maybe the old tales are true?.............Any enlightening would be appreciated...........Thanks Vic Penrod S/S 4563

[Jim Cimarolli]

Thats what I have always heard too Vic, but there is only one way to know for sure how thick it is.

[Kingpen]

true,but theres no one around for 125 miles with a sonic checker.....

[rx dealer]

Vic. I built a .125 over 283 back in the early 80's as a street/strip motor. it had a 327 steel crank and TRW 11 to 1 pistons 461 heads and hydralic cam. It was in my 69 camaro and i would drive it to the track ...one of the best engines i'v had...Luke SS 311

[Joe Schaechter]

If the 721 block has the recessed oil filter for the Chevy II and a 283 bore size I wouldn't let the 870 number under the timing cover throw you off. The 721 Chevy II blocks I have seen with a 283 bore size are thick. The Chevy II block that is really worth $$ is the 350hp/327 block that is cast as a I think a 362 in 1966.

[Jim Parsons]

Vic,
I have had a few of both the 721’s and standard Chevy II 283 blocks through the years and to the best of my knowledge you are correct on all accounts. Another give away for these blocks is the fully machined main bearing web and obviously small journal size.

Also most of the 721’s were the 10-20 (high nickel /chrome) casting which provided a little more strength and better grain structure. They will typically hone up nicer and hold the wall straightness longer, not Bow Tie quality but next best thing in my mind.

Joe is also correct about the OEM L-79 blocks bringing good $$ to the restoration market as I let one go last year. Wish I still had the one that came in my car new but let it go in our car hauler back in the 70’s, Oh well!

Jim Parsons

[Robert Swartz]

Originally Posted by Jim Parsons

Vic,


Joe is also correct about the OEM L-79 blocks bringing good $$ to the restoration market as I let one go last year. Wish I still had the one that came in my car new but let it go in our car hauler back in the 70’s, Oh well!

Jim Parsons

Don't intend to hi-jack this thread but had to chuckle at this. Have a good friend whom is heavily invested in Mopars. We were bench racing at work a few weeks back. I offhand mentioned to him that I once had a complete 340 six pack engine that I'd acquired in a trade. This was back in the mid 80's. I was using a Dodge pu as tow vehicle back then. I was going to rebuild that as a tow engine. Ended up trading the truck for a new Ford dually, sold the engine (for a song by todays standards) for operating funds. What would that engine be worth today, LOL!!!

Oh, and I had one of those 283 Chevy II blocks as well. That was 30 years ago, think I sold it, honestly don't remember.

[Kingpen]

all good and interesting points.it is a recessed oil filter block.. I got it some time back and daughter is 16 now and looking to race.Im building her a 302 and gave some thought to using this block at 4.030 but think I will use a 327 block instead just to keep this one as is because its a good std bore block.I have always like to preserve stuff as much as possible.If a customer comes in with a std block & .060 pistons,I look to see if I have a .040 block to use instead to "save" these old blocks.....thanks for all the info guys,Vic

[Dwight Southerland]

Originally Posted by Jim Parsons

Vic,Another give away for these blocks is the fully machined main bearing web and obviously small journal size.

Jim Parsons

There were other small journal blocks from the '67-'68 era that were obivously forerunners to the large journal blocks that are identified by fully machined main webs, the longer main cap bolts like the large journal blocks used, high nickel content, and main caps with more mass.