Roller cam in a TBI 350

[Manimal]

I am doing head gaskets on my 93 C3500 5.7. The block is provisioned for roller cam. What all do I need? I am thinking of doing a Vortec cam/lifters...what about the distributor gear?

 

[TylerZ281500]

do an lt1 cam, vortec cam isnt anything special but in that regards neither is lt1, just a bit better.

its tapped and drilled? your need the spider tray all the dog bones, lifters, the cam, and the front retainer.

 

[michael hurd]

do an lt1 cam, vortec cam isnt anything special but in that regards neither is lt1, just a bit better.

its tapped and drilled? your need the spider tray all the dog bones, lifters, the cam, and the front retainer.

PLUS the shorter pushrods, and the melonized gear assembly for the distributor.

 

[Manimal]

Do I just order a distributor gear for say a 98 5.7? I had a pushrod bend on #4 exhaust which lead me to pull the head and find the HG between 4/6 was blown. So I thought since I am in there already, I'd just swap in a roller cam...so this is my list..
Cam..LT1 flavor
Factory lifters,pushrods,link bars,spider and hardware for a 98 5.7
Distributor gear for a 98 5.7
Timing Set for the 98 5.7 as well
Am I going to need to get a chip tuned for this now, or will my factory tune work for this?
BTW, Thank You

 

[michael hurd]

My educated guess that it will fire and run OK, perhaps slightly leaner initially than with the flat tappet, but the change in duration isn't going to be as radical as going to an aftermarket larger cam. Vacuum will still be adequate.

 

[michael hurd]

Note: your stock ( worn ) valve springs may not have enough seat pressure for the cam swap. OE GM springs aren't terribly expensive, and you may consider swapping them out for a few bucks more, cheap insurance.

 

[Manimal]

I was going to replace the valve springs...but Im still curious about the DISTRIBUTOR GEAR....do I get one for the Vortec and put it on my distributor? Thanks for all the help.

 

[sntrym]

I just did a Vortec swap into my 95 using TBI injection, and I had some trouble finding the distributor gear. The shaft diameter of my dizzy was .430, but I couldn't find a gear that would work. The Vortec dizzy gear was a different inside diameter. I wound up going with an entire Summit dizzy that had the gear on it already (.430 nonetheless).

 

[michael hurd]

I was going to replace the valve springs...but Im still curious about the DISTRIBUTOR GEAR....do I get one for the Vortec and put it on my distributor? Thanks for all the help.

I don't have both in hand to measure them, but if the shaft diameter is larger on the TBI distributor, anyone with a metal lathe can dial in the gear and enlarge the hole if needed. Aftermarket ones may differ from OE design, I know years ago MSD had a larger shaft than GM OE.

EDIT: if in doubt, obtain one for a 5.7 Caprice, they used roller cams with TBI and TBI distributor, last year was 1993.

ACDELCO 19052845

 

[Steve A]

Distributor Gear (Melonized Iron) GM part numbers: 10457356 (.427 distributor shaft) 10456413 (.491 distributor shaft)