Shoevette

I recently bought a '69 427/435 car. Although the car originally came with that set up, I was aware that the motor had been replaced and was told that the donor was a wrecked '69. I was also told that the manifold was a '68, and the heads were "high performance" '69 heads, whatever that was supposed to mean. I have now confirmed that the car has an L-88 block (code "LO"). With the hope that I have an L-88 in my car, I now need to find out whether the heads were originally mated to the L-88 block from the donor car.

I have checked the casting marks in "Corvette by the numbers", and from what my eyes can see, the heads could be a number of 427 heads, including the L-88. Is there anything I can look for to tell me what I have without pulling the valve covers?

Not to jump ahead, but if I do have an L-88 that was changed to a tri-power set up, what are my options both in terms of value and performance. All input will be greatly enjoyed and appreciated.

Shoevette

MR L88

Your L88 should have the 074 heads if its a later one.842 if its early.Aluminum,of course.

VetteLS6

You need to look at the back of the block for the date casting....69 L88 motors should have 074 heads...the way to really tell is to remove the valve covers and check head castings....if they come up correctly...I would pull the heads off to see to verify thee casting dates of the heads. If your block date is a 68 then the heads could be a different number ETC.....It all begins with a date!... If you have a complete L88 it's worth plenty....I would pull it and drop a crate motor in.

Shoevette

You both tell me I should have 074 heads -- how do I tell without pulling the valve covers or heads (or will I just be guessing without?)?

Little Mouse

L/88s had 12.5 compression and 560, 580 lift with around 310/320
duration, if its in the car running now on pump gas the pistons
are long gone LOL.

RHD '68 L89

Are the heads Aluminium? L88's heads were aluminium. If they are iron they are the wrong heads. Look under the rocker covers. the casting number is near the pushrods in the centre. 840's are iron heads for 435's. 852 are 68 L88/89 and early 69 L88.

Oh and you may want to post the partial VIN. Somebody may have the rest of the donor 69 and be willing to pay you big bucks for the matching motor.

tonyk72

I thought L88's had iron heads and the L89's had aluminum?

MR L88

All L88's had aluminum heads.L89 was the aluminum head option for the l71 435hp tri-power.

Little Mouse

L /88s had those light sort of silver looking things on them LOL.

Ironcross

Plus a whole lot more, 12.5-1 compression on full floating forged pistons hung on a special pink connecting rod with 3/8 rod bolts to 1968 when they went to a 7/16`s special pink rod. Lightweight {15 lb} flywheel with a 10.5 diameter diaphram clutch, open plenum dual plane intake and a TI ignition with a non working vacuum advance to name a few distinct changes from the other 427`s. Most important is the block stamp with "IT" included in the numbers on the pad. If you have these and the other noted changes in the above posts, you have a L88.

Excuse me, for a 69 block "LO" is correct and a tri power will work on the engine very effectively

Shoevette

Thanks for the input, sarcasm and all! (Didn't really think I could get away with this question without a little ribbing).

Shoevette

flynbyu82

Well, now it's your turn to humor us and provide some larger pictures of what seems to me like a beautiful car