4.3 Upgrades

[TRU-JACK]

I have the 4.3 4bbl stock in a 16 with a 23 mirage prop. What should i do first to increase my power? I'm running around 4800rpm in the mid-50's and would love to see 60!
thanks ;)

[CrackerJack]

I have a 4.3lx gen+ with a 2 barrel.
Talking to various people I have concluded the following.
1) Change from 2 barrel to a 4.
2) Better ignition.
3) Performance cam.
4) Stilleto 21 pitch prop. Will increase the
rpm's.
5) Different drive ratio.
6) V-8

You may have another case of the DT's.
DT is short for, (Donzitester=pursuit of speed.) Jack

[TRU-JACK]

Anyone with ignition and cam suggestions. I'm going to be able to work on it in the barn over the winter and will upgrade ignition and cam, but i would appreciate any reccomendations. thanks ;)

[mikev]

the Edlebrock intake will give you 18hp if you have the old non vortec heads. wont bolt up too the new style ones. also some 1.6 ratio rocker arms will give you some more lift without changing cams. that is what I am planing for my 4.3 this winter. I only have the 2bbl carb so I should get a nice boost in power. by the way i turn 5200 rpms on my 4.3 with no problems. mine runs 48 mph in a 19' regazza that is an 1988.

[mikev]

Here is a GM Hp cam for a 4.3 if you dont have a balance shaft but do have roller tappets part# 10134321.

specs duration at .050 224 on both sides
lift w 1.5 rockers 450 intake 460 exhaust
lobe centerline 112

GM says its a Hi performance marine and street cam sounds pretty good to me.

[mikev]

I checked the service manual last night and the 4.3 had a flat tappet cam till 93 when they went to a roller cam and balance shaft so the above cam wont work at all but here is another gm cam that will work on pre 93 motors GM part # 10051165 here is the discription.

This hydraulic flat tappet is a V6, 90 degree version of L-79 small-block V8 cam for 4.3L even-fire engines. It has excellent power and torque, and is for engines without balance shift. The duration at lash point in degrees (intake/exhaust) is 320/320; duration at .050" tappet lift (intake/exhaust) is 222/222; and maximum lift with 1.5:1 rocker ratio (intake/exhaust) is 447/447. Lobe centerline is 114 degrees.