Originally Posted by chevyfreke
it dont look good casting # 10066036 with a small tab has 576114
This is a Mexico casting used a lot for the Targetmaster and Mr. Goodwrench replacement engines. It will not accept Gen I, LT1 or LT4 heads.
But they can be modified to work on older blocks, the large coolant holes on the rear portion of the heads can be welded up and a new hole drilled following a Gen I head gasket pattern. Then the heads have to be milled as the welding will pooch them a bit. An external coolant return has to be made into the front of the heads where the vapor return hole is located. You have to use the LT1 conversion to carb intake which is pricey this also reverts the distributor to the conventional rear mounted position. Then you have to fabricate a coolant return manifold. There are several ways to do this, a thermostat adapter for each head with a hose to a Y fitting to get to the radiator, One thermostat housing and a hose from the right head that then flows to the radiator is another config, this is not unlike the coolant return of the 1950's era Chrysler Hemi. The last would be similar to the preceding except the thermostat is mounted in a housing fastened to the front of the intake and connected to each head with a hose. The rear vent holes would be plugged off except perhaps for a small vent line because in conventional cooling it is necessary that the bulk of the coolant enter the block cold. As it flows from front to rear is warms. Most of the coolant then flows into the back of the head and gains more heat as it flows forward to the return. This balances the engine's heat budget by placing the coolest cylinders 1 & 2 at the front having the hottest combustion chambers. At the rear, 7 & 8 have the hottest cylinder walls but the coolest combustion chambers. I know, it's crude, but for all but heavy competition motors it works pretty well.
The cost of modifying the LT1 heads is considerable, especially if they need a valve job, by the time you're done saving money you will spend about as much as a new set of Vortecs. Guess how I know? but actually this conversion is done more frequently than you might expect.
I say expect to pay about $150 for welding and milling. This goes better if you buy a piece of 3/8ths to 1/4 thick aluminum and make plugs the welder can install rather than trying to fill that hole with bead. The coolant returns can be done simply with some stainless fittings from Precision Stainless and some heater hose to a common return with the thermostat, Morso makes some if you can't carve your own, http://www.moroso.com/catalog/catego...?catcode=26342
hers' some other solutions http://www.moroso.com/catalog/catego...?catcode=29400
So just bring money and ability, as this can be done.
Oh! The intake, that's around $350, but a set of Vortecs take a pricey intake as well.