1970 3963512 Block Strange One

[BARRY]

HI WHEN GM BOUGHT OUT THE 454 WITH THE LONGER STROKE THE FIRST BATCH ALL HAD 4 BOLT MAINS??? I HAVE SEEN THIS BLOCK BOTH WAYS

[3macs1]

Never knew that Barry. Wish I did. Been around these big blocks since my first chevelle in 76 and worked on dozens of them when I worked in the service station. Never before did I see a 4 bolt block on a factory oval port other than the tall 366 and 427 truck blocks.There probally was not that many in the initial run of 70 454's.
Any idea Rick or Mr.70 how many oval port 512's may have been sold with 4 bolt mains and steel cranks. Rods and pistons were oval port gear.

[370454s]

The one I have in my 70 Chevelle is a 4 Bolt Steel Crank 390 HP,454. Motor came out of a 70 Caprice that was sold new in Oct 69.

[Hotrodpaul]

Probably a supply or engineering decision based on the new large displacement engine. GM may have done it for warranty prevention reasons. I presume the steel crank was non Tufftrided and non Crossdrilled.

Paul

[69L72RS]

What date range was the first batch of engines (454 CID) made.
I have a 454 2-bolt block coded T0806CGV.
Just curious.
Eric

[Mr70]

The CGV was a 345HP engine.
I've not seen any 345HP's w/4 bolts yet,so far only 2-bolt mains.
The only EARLY casted 1970 non LS-6 coded 512 4-bolt blocks I've seen so far were 390HP engines slated for Impala-Police & Taxi useage.

[olredalert]

------A couple of years ago I pulled two oval-port 351 67 dated complete engines out of a completely dry-rotted Pacemaker boat. They were both 4-bolt main along with the oval-port, but one was reverse rotation. Both were very low hour, beautiful standard-bore pieces, and, although low compression had the good rods and crank. Both the blocks are sitting in restored 67 Corvettes today........Bill S

[nuch_ss396]

Bill,

Were the piston domes on these marine engines the standard 10.25:1 design? With oval ports, I would expect so.

[3macs1]

Steve:
I am not sure if it had a 6223 crank. I asked specifically on the dimpled rods and pistons and he told me the shop that is rebuilding it told him they were just standard oval port but the crank did not have to be cut and was forged.
Also the air cleaner never had a 345 hp or 390 hp decal on it, just 454 and that was original. It was a fully loaded impala that my grandmother remembers was a salemans demo with 2000 miles on it when they purchased it in early january of 70. So it was a early production.They wanted the big engine to pull a camper.
The car was loaded with air, ps,PDB, tilt, PS, PW, PL, rear defrost,8t,posi, fender skirts, delux belts,remote mirrors, etc.

[nuch_ss396]

[ QUOTE ]
.....They wanted the big engine to pull a camper.... .

[/ QUOTE ]

OK, silly question time. Did the full sized cars come with
a towing package if ordered? If so, would that possibly
incorporate a 4-bolt block? I've never heard of this before
myself, but you never know.

Steve