CASTING #

[EPWJOE]

I HAVE A SET OF 552 CASTING HEADS .ARE THESE A GOOD HEAD? THEY WILL BE USED IN A CREW CAB CAR HAULER, APPROX 12000 LB LOADED. ANY INFO FOR MOTOR COMBO FOR THIS TRUCK WOULD BE HELPFUL.

[bondsman]

youre heads are late model 120cc heads with no smog rail.
they yield im told more low end torque stock than the 76cc stock head.
but the 76cc will flow better with head work, plus as you know the 76cc
heads will give you the higher compression than the 120cc heads with
most of todays aftermarket pistons.the largest valves that you can install for youre head is 2.11(i) & 1.77(e) and the 76cc you can go larger on
both intake & exhuast.it is all in what you are trying to achieve and
how you want to build youre caddy. [/quote]

[EPWJOE]

THIS TRUCK HAS A CADDY IN IT NOW, STOCK EXCEPT FOR INTAKE AND HEADERS. I THINK I HURT SOMETHING , RING MAYBE SMOKING FROM LEFT SIDE . JUST CURIOUS AS TO WHAT COMBO WOULD GIVE GOOD PERFORMANCE AND MAYBE HELP FUEL MILAGE. I HAVE ANOTHER ENGINE WITH THOSE 552 CASTING HEADS AND I PLAN TO CHANGE OUT.
THANKS FOR ANY AND ALL INPUT

[bondsman]

as far as the smoke goes pull the spark plugs first and look to see
if they have oil deposites on them thats a good indication that the
stem seals may need to be replaced. the valve train components on
a caddy is realy its only week link. as far as fuel economy a tall gear at
the rear with not enough cam will cause a poor fuel economy and give you
poor performance. Al has agreat selection of cams. becarefull with lift
on the cam cause stock caddy springs are not strong and can easily break.

[Andy V]

Those 552 castings can make a great low compression towing motor, with basically stock parts. You need to determine what short block you'll be using though, if you have a high compression motor with 76cc heads and swap those 552's on it won't work. You need pistons with compression height suited for the 120cc (552) heads to get 8.5:1. I believe MTS sells stock replacement pistons for this if you need them.