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View Full Version : TBI-fed L31 Cam Recommendations



JCampbell
11-17-2019, 01:48 AM
Dropping a fresh L31 into my TBI-swapped 86 K20 next week. Just a stock 2-bolt reman from Jegs. Still sticking with TBI, but can't help but wonder if I would benefit from a small cam change before I put the intake on and drop the new engine in.

In the past, I've been real happy with the CS1014r on flat tappet TBI engines; but the L31 being a roller cam affair, I'm looking for a recommendation.

If it were you, would you consider the cost and hassle on a daily driven street truck worth it, or would you stick with the stock grind for now?

dfarr67
11-17-2019, 03:01 AM
Go with the hotter of the two LT1

Fast355
11-17-2019, 07:40 AM
GM 12677151

215/223 @ 0.050
0.473/0.473" lift
108 LSA
109 ICL

It comes from GM in the SPO 357 HP 350.

Its basically a L31 with a marine 0.051" compressed head gasket that drops compression to 9:1 and a cam change.

Friend of mine had one put into a 4 bolt main L31, broken in and dyno tuned on an engine dyno. 385 hp @ 5,600 and 422 tq @ 4,000 with a performer rpm intake, a 650 vacuum secondary holley and 1 5/8" long tube headers. It made 400 ft/lbs at 2,500 rpm. Pulled 16 in/hg vacuum at 650 rpm.

I had one in my Express van with head work, thorley tri-ys and a looser than stock converter in the 4L85E. It had great manners and made good power.

I have tuned way bigger cams with the stock later TBI computer but it is up to you and your experience tuning to make it run right. A stock L31 is a big enough chore for a first time tuner.