Corvette engine?
Thread Starter
Instructor
Joined: Sep 2009
Posts: 142
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From: Ramer Tennessee
Corvette engine?
As you can see by my photo, I own a 63 convertible, but I recently bought a 46 chevy pickup and have a corvette related question about it. The previous owner had it since 1969. He installed a v8 and muncie 4 speed years ago and I'm trying to figure out what it is. He told me years ago that it was a 327, but when I bought it he called it a 350. According to the info I found, the casting numbers say it could be either. Looking at the lime book on the ncrs page it shows a suffix of HT being a corvette engine. I know that nearly every v8 transplanted engine in an automobile for sale is a "corvette" engine. The casting numbers are 3914678, which I believe show to be1968. The stamped numbers on the passenger side deck are 18S403129 VI0I8HT. Does anybody have any more info?
Racer
Joined: Oct 2011
Posts: 453
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From: Honaker Kentucky
Nice find. 1968 Corvette 327 350 horsepower with the 4 speed transmission. In my opinion one of the best small blocks ever made even if GM did short change it with the cast iron intake manifold.
Burning Brakes
Joined: Mar 2005
Posts: 1,054
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From: San Antonio Texas
I have the same block. I was only able to "assume" mine was a 300hp 327 corvette mill by the suffix and the stuff that came with it, ie: 1968 tach drive distributor and accessories etc,I was hoping to build it into a hopped up 327 and make it look like a period correct higher hp 327 motor to put in my 64, but on mine, the crank case vent at the rear of the block near the distributor hole is just a flat pad,,,, not a hole.... so I'd have to use 350 valve covers which would defeat my plan....
Interestingly, I can only find the HT suffix in the years 65-69 except the 68. So the suffix letters stamp doesn't match up with the (68 only) casting number. Are you sure you read the pad stamp correctly? In 65-67 the HT's are 350hp vette engines. In 69 they're 255 hp engines in larger cars...
Interestingly, I can only find the HT suffix in the years 65-69 except the 68. So the suffix letters stamp doesn't match up with the (68 only) casting number. Are you sure you read the pad stamp correctly? In 65-67 the HT's are 350hp vette engines. In 69 they're 255 hp engines in larger cars...
Race Director
Joined: Oct 2000
Posts: 12,652
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From: Shamong, NJ
The VIN indicates the engine came out of the 3129th 68 Corvette built, and the engine was assembled at Flint MI (the V), on October 18th (1018) and is a 327/350 (HT).Interestingly, I can only find the HT suffix in the years 65-69 except the 68. So the suffix letters stamp doesn't match up with the (68 only) casting number. Are you sure you read the pad stamp correctly? In 65-67 the HT's are 350hp vette engines. In 69 they're 255 hp engines in larger cars...
Burning Brakes
Joined: Mar 2005
Posts: 1,054
Likes: 715
From: San Antonio Texas
HT is a 68 327/350. The "HT" code is listed in the NCRS 68-82 Specifications Guide and also in the Lime Book. A link to the Lime Book can be found in the C1/C2 Forum General Section Sticky's. For 65-68 the "HT" code is a 327/350 in a Corvette, for 69 it is a 350/255 with a 2 bbl carb in a passenger car (Chevelle, Camaro, Nova, Impala).
Burning Brakes
Joined: Mar 2005
Posts: 1,054
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From: San Antonio Texas
From Wilcox:
HE 327 Base 300 Rochester Q-jet & Manual Transmission
HO 327 Base 300 Rochester Q-jet & Turbo Hydra-Matic
HP 327 Base 300 Rochester Q-jet, A/C, P/S & Manual Transmission
HT 327 L79 350 Rochester Q-jet, Special Cam & 4-Speed
1968 Corvette Engine Block Codes
1968
Code Number EngineHE 327 Base 300 Rochester Q-jet & Manual Transmission
HO 327 Base 300 Rochester Q-jet & Turbo Hydra-Matic
HP 327 Base 300 Rochester Q-jet, A/C, P/S & Manual Transmission
HT 327 L79 350 Rochester Q-jet, Special Cam & 4-Speed
Safety Car
Joined: May 2014
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The VIN indicates the engine came out of the 3129th 68 Corvette built, and the engine was assembled at Flint MI (the V), on October 18th (1018) and is a 327/350 (HT).HT is a 68 327/350. The "HT" code is listed in the NCRS 68-82 Specifications Guide and also in the Lime Book. A link to the Lime Book can be found in the C1/C2 Forum General Section Sticky's. For 65-68 the "HT" code is a 327/350 in a Corvette, for 69 it is a 350/255 with a 2 bbl carb in a passenger car (Chevelle, Camaro, Nova, Impala).
Race Director
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From: T-Town WA
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Burning Brakes
Joined: Mar 2005
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From: San Antonio Texas
Racer
Joined: Oct 2011
Posts: 453
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From: Honaker Kentucky
bigger cam, 2.02 intake valve heads, higher compression ratio. It used a cast iron intake manifold. This is the only the only 327 350 horsepower corvette engine to use a cast iron intake manifold.
Race Director
Joined: Oct 2000
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From: Shamong, NJ
To my knowledge, the "678" block, like all small blocks from 68 on, used the larger 2.45" main journals.
The Q-Jet and distributor used with the 327/350 were tuned differently too, or at least carried different part numbers than those used on the 327/300.
The 68 L-79 used the low rise cast iron intake, because the earlier aluminum intake wouldn't fit under the standard 68 small block hood. Like the 68 327/350, the 69-70 350/350 used a cast iron intake also. The 70-72 LT-1's used a high rise aluminum intake similar to the 64-67 L-79 intake, and used the big block hood to gain the extra clearance needed for the aluminum intake.
The 68 L-79 used the low rise cast iron intake, because the earlier aluminum intake wouldn't fit under the standard 68 small block hood. Like the 68 327/350, the 69-70 350/350 used a cast iron intake also. The 70-72 LT-1's used a high rise aluminum intake similar to the 64-67 L-79 intake, and used the big block hood to gain the extra clearance needed for the aluminum intake.
Race Director
Joined: Oct 2000
Posts: 12,652
Likes: 3,110
From: Shamong, NJ
The 3914678 block is a 1968 only casting. It was only ever used for 68 327's in Corvettes, Camaro's, Chevelle's, Chevy II's and full size Chevrolet's; the 302 in 68 Camaro Z/28's; and the 350 in 68 Camaro SS350's. If it was a 69 350 the block casting number would likely be 3970010, the most common 350 block, or possibly 3958618, but it couldn't be a 69 engine with a "678" block. This will confirm it's a 68 engine.
Check for your block's casting date. It should be on the trans mount flange, on the right rear of the block, on the opposite side of the block from where you found the casting number. I bet you'll find it something along the line of Jxx7, "J" for October, xx for the day of the month (two digits identifying the day, 01 to 31), and a "7" for 1967.
