Hi C4 guys, I am in the end stages of getting my L31R motor and 700R4 trans into my C3, I am running an 86 ECM and TPI. The problem I am having now is, my block hugger headers are hugging my knock sensor. The headers fit both sides of the block the same, so I can't just switch sides. I need to know if I can move my knock sensor to somewhere else on the motor? If so where?

Thanks for your time.
Zorro

 

I read a magazine article once on a s-10 tpi swap where they drilled and tapped a hole in the motor mount, the area that bolts to the block and it worked OK.

 

Don't have an answer for you but I am curious to what an L31R motor is?

 

From what I could tell from reading up on it. It's about the last of the 4 bolt main 350s. The only down side is the cam, and that can be fixed. As it is it makes up to 255hp.


Chevrolet Performance 12530283 - Chevrolet Performance 1996-2000 Truck 350ci L31-R Long Block Assembly

Chevrolet Performance#809-12530283
L31 HD Engine
1996-2000 Chevy/GMC Full-Size Truck
1996-2002 "G"/Savana/Express Van
1996-99 "P" Van over 8,600 GVW
3/4 and 1-Ton only
Not for Marine Use

FREE SHIPPING
& HANDLING!
$1,919.99


Chevrolet Performance 12530283 - Chevrolet Performance 1996-2000 Truck 350ci L31-R Long Block Assembly

Free Shipping!

The Chevrolet Performance Truck 350ci L31-R Long Block Assembly was designed as a direct replacement for 1996-2000 GM Full size Trucks and 1996 -2002 Full size Vans. These engines are manufactured using the latest in high tech computer controlled equipment and are backed with a Limited 3 Year / 100,000 Mile warranty!

Specifications:
1986-2000 style block, 4 bolt mains
1pc rear seal nodular iron crankshaft
Powdered metal connecting rods
Hypereutectic pistons 9.4:1 compression Ratio
Hydraulic roller camshaft: Int Lift .414", Exh Lift .428", Int Duration @.050" 191, Exh Duration @ .050" 196, Lobe Centerline-111
Vortec cylinder heads - 64cc, 1.94'' intake valve, 1.50'' exhaust valve
Also includes: Oil pan, timing cover, valve covers, harmonic balancer
JEGS Easy Kits are designed by JEGS professionals so you get all the parts you need.

GM Warranty

Zorro

 

Id go, long tube headers. Do you need to pass smog ?

 

A Vortec truck motor; '96 -'00

L31 was it's GM ID just like L98 , LT1 . LT5

 

No I don't need to pass smog. Compared to when it had a carb, it is much cleaner running, and would most likely pass. I may end up going with long tubs, but the ones I have are paid for, and except for the knock sensor they fit great.

Zorro

 

I found a solution. I am posting it, so anyone else with this problem can find it with a search. Knock sensor adapter, click on LINK

 

Hey Zorro well the link which you provide about knock sensor adapter and also its types like Ron francis,Caspers electronics etc..Thanks!!


S-Type Load Cells

 

so where did you mount the kb41 adapter on the oil pan?

 

It should work on any pan bolt, just stay back a little from the timing chain. I read somewhere that it can make a noise that will confuse the knock sensor.

 

thanks it looks like its just behind where it would mount in the block

 

Yep, that's where I put it just far enough from the header to not melt. If you look behind the header you can see where it would normally go.

 

[QUOTE=Zorro O Where did you get that engine for that price. I'm thinking of replacing mind on my 85 with one. But haven't found one for that low of a price. So far it's $1,959.99 from RADLEY CHEVY back east. Please let me know how it pulls with the stock CAM. Do you know the power output of this L31-R. That info would really help me decide on it. TIA

 

[QUOTE=BV85;1594369774][QUOTE=Zorro O Where did you get that engine for that price. I'm thinking of replacing mind on my 85 with one. But haven't found one for that low of a price. So far it's $1,959.99 from RADLEY CHEVY back east. Please let me know how it pulls with the stock CAM. Do you know the power output of this L31-R. That info would really help me decide on it. TIA [/QUOTE]

I got it from summit with free shipping to my house. This was in 2013 I don't know what they go for now. At the time I bought mine they claimed 255 HP was possible. I'm running a TPI injection system and a 700r4 trans, with real dual exhaust. I don't know how much power it actually makes, but I can say it makes a ton of torque. With the old motor and trans it got a solid 9mpg on the freeway (I drove it home from Los Angeles to Seattle when gas was $5.00+ a gallon, the car has a 24 gallon tank. I thought my credit card was going to die of exposure) it's getting over 19mpg now.
Four years ago I could not swing an LS motor and all the stuff needed to install it, and nobody around would or could do it or help. With the Small block Chevy I just did it my self. I'm not sure I would go LS even now but I would go with a newer electric controlled transmission. The L31-R is the only way I know of that you can still buy a 4 bolt main 1 piece rear main seal small block new from chevy. I understand that a new cam can be installed that will work with the heads and add more high end. But I'm having too much fun with the torque right now. If I want a lot more power some day it's only a head job and cam away. Ok that was long winded, but I hope it helps. Summit has it for $2,078.97 now with free shipping. Jegs couple bucks cheaper with free shipping.