Jan 30, 2002 · On the street, the Edlebrock O port heads will work better and make at least 550 HP. I have a set of the L88 heads that I don't need if anyone is interested. they work really well above 4000 RPM but the ports are really a bit big for a 427 or a 396. I decided at the last minute to but brand new heads for my 427 build up since I went with a hyd cam.

May 26, 2002 · The "074" heads were state of the art when they made their debut in the late 1960s, but technology has passed them by to some degree. They are still a more than adequate cylinder head for performance applications and if they are complete, check out OK on pressure and zyglo tests, and are paid for to boot, I see no reason not to use them.

Dec 19, 2009 · Factory Correct Resto - L88 Aluminum Cylinder heads - I bought an engine a few years ago and was told that it had L88 heads. All I know, without getting the casting #'s, is that they are aluminum, D-port, 4 center bolt, angled spark plugs and they came with corvette emblems on the valve covers.

Jul 3, 2008 · L89 - same as L71 (tri power carbs) but aluminum heads L88 single Holly 4 barrel carb aluminum heads. I think both are solid lifter 4 bolt main motors, so really I think the main difference is the intake / carb setup, and of course several thousand dollars.

May 4, 2005 · It is true that they were the same for 67-68; however, the 69 L88's and the new ZL1 option got the new open chamber heads. The 69 L89 still used the closed chamber heads. FYI, this was how they reduced the compression on the LS6 motors.

Feb 22, 2005 · Factory Correct Resto - 69 L88 heads what are they worth?? - I have come across a set of 69 L88 Aluminum Heads. Casting number 3919842. These were purchased from a GM dealer 8 years ago and have NEVER been machined. All the necessary Valves and hardware also available. These heads have the snowflake with the W in the...

Mar 18, 2004 · The L88 had higher compression, the aluminum heads, more camshaft, different carburetor, different intake, no pcv system, and a different advance curve on the distributor. It made about 100 more true gross SAE HP than the L72 (550 vs 450). The respective ratings of 430 and 425 HP were a joke. Dyna

The L88 is a 427c.i. powerplant fitted to Corvettes from 1967-1969. Not many, mind you, with only 20 so-equipped in 1967, 80 in 1968, and 118 in 1969. That makes a grand total of just 218 L88-equipped Corvettes floating around. Officially, the 1967 L88 is rated at 430 hp @ 5200 RPM, 460 lb/ft torque @ 4,000 RPM. More on the power figures later.

Feb 11, 2009 · The GM heads use the 12462970 springs The L88 used the 3916164 springs. The new springs have more seat pressure and a heavier rate (hydraulic roller springs). Might want to respring the heads.

Oct 24, 2015 · Basically Chevrolet had aluminum heads out on big blocks as early as 1966, but with problems (Penske cars, etc.). They had HD and L88 stuff out during this time prior to official production releases. In Jan 1967 aluminum heads still were being troubleshot by testing, but it wasn't until March 1967 where the L88's and L89's were getting released.