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smokediver
06-24-2003, 07:35 PM
I am changing over from a cast iron 2bbl. manifold to a aluminium 4bbl. do I need and throttle linkage adapters ? the carb and manifold are both edelbrock..FYI...Edelbrock now makes a vor-
tec 4bbl. intake for the 4.3 .performer series.
thanks in advance.. i also have the imco thumper manifolds and risers on the way.. will post how it works out..

Rootsy
06-24-2003, 09:43 PM
yes you will need a new throttle bracket and the cable mount/stud. there are a few different styles, one is a plate that goes between intake and carb (2 gaskets required) + stud/cable mount and another for at least holleys is one that mounts on the studs on throttle side. if you are going quadrajet or weber (carter AFB)then you can get the stock merc brackets for these setups and use those...

smokediver
06-24-2003, 11:16 PM
thanks rootsy...

mikev
06-25-2003, 10:35 AM
i just did that swap last year on my 4.3 everything hooks up perfect but you will need the linkage bracket from a 4.3 that came with a 4 barrel carb. you can get it at any mercrusier dealer there about $40 the cable hooks up perfectly once you get the bracket. be sure and run a braided steel fuel line from the fuel pump to the carb do not use rubber fuel line. this was a great upgrade i gained 400 rpm and you can realy feel the 4bbl kick in when you jump on it. check it after you run it a few times my secondaries stopped opening up after about the third trip out. i needed to ajust the linkage that keeps them closed when its cold. it was not disingaging when it warmed up

smokediver
06-25-2003, 10:49 AM
mike, thanks for the info.. did you do the exhaust as well ?

mikev
06-25-2003, 01:11 PM
no i did not do the exhaust so i will be waiting to see how it works for you are you going to do the intake and exhaust at a seperate time so you can see which gives you the best gain in power.

my plans for this winter are ported and polsihed heads with bigger valves and a cam upgrade to gm cam here is the part # and specs for it

10134321 Hydraulic Roller Tappet
This hydraulic roller tappet is a high performance street and marine cam for 4.3L even-fire engines. Use only with roller tappet block on engines without balance shift. The duration at lash point in degrees (intake/exhaust) is 321/316; duration at .050" tappet lift (intake/exhaust) is 224/224; and maximum lift with 1.5:1 rocker ratio (intake/exhaust) is 450/460. Lobe centerline is 112 degrees.

smokediver
06-25-2003, 03:27 PM
mike, i will let you know.. I am doing it all at once as i need to pull the motor for the manifold change. look a little closer into the cam. I believe the vortec is balanced and the cam is not for our motors.. i could be wrong..

mikev
06-25-2003, 03:39 PM
mine is an 88 without the balance shaft so i can run it. what year is yours because if it is a true vortec engine that manifold will not fit there is a different bolt patern for the intake manifold. i think the changeover was 97 the engines before that were called vortec but had the same heads. the new heads only have 4 bolts on each side of the intake not 6 like the old ones..

smokediver
06-25-2003, 07:58 PM
mike.. i have a 1998 however edelbrock is making a intake for that engine now. it is new for this year..

mikev
06-25-2003, 10:10 PM
cool i did not know that, the true vortec heads flow as much stock as a set ported and polished old ones do. If i knew they were coming out with an intake for them I would have waited and upgraded heads at the same time o well. I am going to throw a 1" carb spacer with the four holes in on mine should help out with the bottom end torque I will let you know how that works out.