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#51 | |
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Join Date: May 2016
Location: Henderson NC
Posts: 975
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Re: What GM create engine to buy for 3/4 ton 72 C20
Quote:
The center bolt valve covers were an improvement over the old style and a good improvement if you ask me. The adapters are just creating more places for the covers to leak. I'm as old school as anyone but since I installed my motor there is no way I would go back to the old perimeter style covers. If you want more HP just install a good intake and 4 barrel carburetor with long tube headers and 2 1/2 inch exhaust. You can also install a MSD ignition system. All this will help the motor to breathe and the extra spark doesn't hurt. This is how I have mine set up and it has a lot of power. You can also add 1.6 rockers on the intake side. I started to do this but learned I might have to drill out the holes for the push rods so I decided not to mess with it. I didn't want to pull the heads or take a chance of getting metal in my motor. Last edited by garyd1961; 11-18-2017 at 08:54 PM. |
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#52 |
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Location: Godley, TX
Posts: 17,964
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Re: What GM create engine to buy for 3/4 ton 72 C20
Have never had to do this and have used 1.6 rockers before. Where did you hear this? Is this Vortec-specific or something? Not the case with stock Gen 1 sbc.
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#53 |
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Location: Harrison, Arkansas
Posts: 9,815
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Re: What GM create engine to buy for 3/4 ton 72 C20
WE have 1.6 roller tips on both old style and vortec heads. As I remember we had to use thick valve cover gaskets.
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other Larry Build thread, Arkansas K10 https://67-72chevytrucks.com/vboard/...=755797&page=5 The ability to speak several languages is an asset, but the ability to keep your mouth shut in any language is priceless. |
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#54 |
Registered User
Join Date: May 2016
Location: Henderson NC
Posts: 975
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Re: What GM create engine to buy for 3/4 ton 72 C20
I have never used 1.6 rockers but believe it's just for the Vortec heads. You may get by without drilling but some say you need to drill out the passages for the push rods with a 1/2 inch drill bit to be on the safe side.
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#55 |
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Location: Godley, TX
Posts: 17,964
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Re: What GM create engine to buy for 3/4 ton 72 C20
Interesting, thanks, had never heard of that. More reason to install the cam one really wants up front! I think the HT 383 cam might be a nice addition to the L-31R, as some have mentioned above. I can't think of any reason that wouldn't work just fine, and with standard 1.5 rockers.
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#56 | |
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Location: Orem, Utah
Posts: 7,915
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Re: What GM create engine to buy for 3/4 ton 72 C20
Quote:
__________________
I have sworn upon the altar of God, eternal hostility against every form of tyranny over the mind of man. - Thomas Jefferson |
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#57 |
Senior Member
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Location: Godley, TX
Posts: 17,964
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Re: What GM create engine to buy for 3/4 ton 72 C20
So, here's an interesting find from Radley - since we've been talking about putting an HT383 cam into an L31R, isn't the below kinda "that"?
350, 9.1:1 (the 383 compression ration though, not the L31's) - but a higher lift cam than even the HT383. I sure don't need a forged crank like the 383, so can save some $ there. So basically an L31R with a slightly lower (but still good - same as the HT383) CR and a more aggressive cam than the L31. While not as much hp/torque as the HT383, still a decent improvement over the L31R, and you don't have to rip a factory built one apart to install a new cam... This kinda seems like a factory version of what I'd want to do to an L31R anyway. Hmmm. (the chrome would have to go though... ![]() https://www.ebay.com/itm/OEM-NEW-Che...19.m1438.l2649 Specifications: Power: 330 HP AT 5000 RPM, 380 ft. lbs. of torque @ 3800 RPM Displacement: 350 CID, 5.7L Bore x Stroke: 4.00” x 3.48” Compression Ratio: 9.1:1 Block: Cast Iron, 1 piece rear seal, 4-bolt main caps Crankshaft: Nodular Iron Connecting Rods: Powdered Metal Steel Pistons: Cast Aluminum Camshaft: Hydraulic Flat Tappet Cam Lift: .435” Intake / .460” exhaust Cam Duration AT .050”: 212 deg. Intake / 222 deg. Exhaust Lobe Separation: 112.5 Degree Cylinder Heads: Vortec Cast Iron, 3/8” pressed-in rocker studs Combustion Chamber: 64cc Valves: .194” Intake/ 1.50” Exhaust Rocker Arms: Stamped Steel, 1.5:1 Ratio Valve Springs: 10212811 Balance: Internal Maximum GM Recommended RPM: 5500 Ignition Timing: Base 10 degrees BTDC, 32 degrees total Here it is for $2500 ($300 less), but I'd probably still go the dealer route - Radley. Reputation. https://www.ebay.com/itm/OEM-NEW-Che...4383.l4275.c10 EDIT: an important note, the power and torque band is noticeably shifted north in this motor than an HT383, or even the L31R. Guess there's no way around 383 price if you want 383 #'s! Ha. Can build it for a little less, or go with the warranty factory crate. I know what I want (383). I'd have a hard time choosing between the L31R and this HO350. L31R may be more usable for a truck. That's what it's made for. The HO 350 is perhaps more of a Camaro crate... Anyone have both that can speak to the seat of the pants diff between an HO 350 (19210007) and an L31R? Last edited by jocko; 11-22-2017 at 07:05 PM. |
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#58 |
Registered User
Join Date: May 2016
Location: Henderson NC
Posts: 975
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Re: What GM create engine to buy for 3/4 ton 72 C20
That's a flat tappet cam, I would stick with the L31-R and a hydraulic roller. There is no way I would pay more for a motor with a flat tappet cam. GM didn't switch to a hydraulic roller for nothing, they would have stayed with the cheaper flat tappet if they didn't have a good reason to switch.
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#59 |
Senior Member
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Location: Godley, TX
Posts: 17,964
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Re: What GM create engine to buy for 3/4 ton 72 C20
Thanks Gary. Yeah, that's why I was surprised, ALL their other Vortecs have roller cams that I can see, and even one of them, at one dealership, lists the HT383 incorrectly with a flat tappet, so thought maybe this one was incorrectly documented also. I agree, better to have a roller. I think I'd be happier with the lower torque band of the L31R anyway to be honest. If ONLY GM would come to this website and realize they need an L31R with an HT383 cam in it, all would be solved
![]() I saw above a few mentions of painting the crate motor chev orange - does anyone have any pics of a crate L31 painted orange they could share? I'm curious how noticeable the manifold differences are - I'm assuming not very. And, my apologies to Chilly, I feel I've hijacked a bit. ![]() |
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#60 | |
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Location: Harrison, Arkansas
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Re: What GM create engine to buy for 3/4 ton 72 C20
Quote:
I do know the 383 we have in the BLazer is fun.
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other Larry Build thread, Arkansas K10 https://67-72chevytrucks.com/vboard/...=755797&page=5 The ability to speak several languages is an asset, but the ability to keep your mouth shut in any language is priceless. |
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#61 |
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Location: Harrison, Arkansas
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Re: What GM create engine to buy for 3/4 ton 72 C20
RE; orange paint.
A friend of mine put the L31 in my 55. He didn't paint it. It would look a lot better to me painted Chevrolet Orange. I have not warmed up to the center bolt valve covers. I am going to buy adapters, so I can put old style valve covers on it.
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other Larry Build thread, Arkansas K10 https://67-72chevytrucks.com/vboard/...=755797&page=5 The ability to speak several languages is an asset, but the ability to keep your mouth shut in any language is priceless. |
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#62 |
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Join Date: May 2016
Location: Green Bay, WI
Posts: 134
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Re: What GM create engine to buy for 3/4 ton 72 C20
Good info here. If one were to go the L31-R route how would that work with the electronic fuel pump?
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#63 |
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Location: Godley, TX
Posts: 17,964
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Re: What GM create engine to buy for 3/4 ton 72 C20
He's referring to the HO350 I posted the link to in post #57.
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#64 | |
Senior Member
![]() Join Date: Oct 2009
Location: Godley, TX
Posts: 17,964
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Re: What GM create engine to buy for 3/4 ton 72 C20
Quote:
![]() Guess I just answered my own picture request, forgot I had this one saved somewhere. |
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#65 | |
Registered User
Join Date: Feb 2015
Location: TX Hill Country
Posts: 150
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Quote:
Posted via Mobile Device |
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#66 |
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Location: Orem, Utah
Posts: 7,915
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Re: What GM create engine to buy for 3/4 ton 72 C20
If you're going to use a carburetor you'll need an electric fuel pump and a fuel pressure regulator.
__________________
I have sworn upon the altar of God, eternal hostility against every form of tyranny over the mind of man. - Thomas Jefferson |
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#67 |
Senior Member
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Location: Harrison, Arkansas
Posts: 9,815
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Re: What GM create engine to buy for 3/4 ton 72 C20
I run an electric fuel pump with my L31.
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other Larry Build thread, Arkansas K10 https://67-72chevytrucks.com/vboard/...=755797&page=5 The ability to speak several languages is an asset, but the ability to keep your mouth shut in any language is priceless. |
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#68 |
Registered User
Join Date: May 2016
Location: Henderson NC
Posts: 975
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Re: What GM create engine to buy for 3/4 ton 72 C20
Some pumps don't need a pressure regulator. Right now I'm running a Holley Mighty-Mite without a regulator. I really didn't think the little Mighty-Mite pump would be worth a darn when I first saw it but it has worked flawlessly so far.
If any of you do get the Mighty-Mite be aware there are 2 different versions. I have the 400 hp rated one, don't have the part # right now. |
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#69 |
Registered User
Join Date: May 2016
Location: Green Bay, WI
Posts: 134
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Re: What GM create engine to buy for 3/4 ton 72 C20
Hey Gary could you post a pic where you mounted the fuel pump? Says that it should be within a foot of your tank.
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#70 |
Registered User
Join Date: Dec 2016
Location: Hawthorne, NV
Posts: 33
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Re: What GM create engine to buy for 3/4 ton 72 C20
Great disuccusion on the L31r.
I’m looking to run my factory clutch linkage on my 64 c10. Does anybody know if the block has the provision tapped for the ball stud? I’ve looked all over and can’t find any clear pictures, or information on this. Thank you. |
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#71 |
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Join Date: Aug 2009
Location: Bowser
Posts: 13,622
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Re: What GM create engine to buy for 3/4 ton 72 C20
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#72 |
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Join Date: Nov 2014
Location: Bigfork, Montana
Posts: 1,137
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Re: What GM create engine to buy for 3/4 ton 72 C20
My L31 did not. The boss is there, I drilled & tapped mine.
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#73 |
Registered User
Join Date: Dec 2016
Location: Hawthorne, NV
Posts: 33
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Re: What GM create engine to buy for 3/4 ton 72 C20
Thank you for the responses. I feel confident to drill and tap the provision on the block after some research.
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#74 |
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Join Date: Jan 2016
Location: Barber City, CA
Posts: 4,783
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Re: What GM create engine to buy for 3/4 ton 72 C20
if I decide to buy a crate motor over building one of mine, I'm defintiley going this route..
just under $6k with EVERYTHING complete.. huge time saver hunting all that down.. if GM packaged a 383 turn-key like this, I'd already be all over it.. Chevrolet Performance SP350 Turnkey Long Block Crate Engines 19367084 They put out 385 hp with loads of low-end torque. In fact, the engines produce 405 lbs.-ft. of torque by only 3,600 rpm for a thrilling feeling of immediate performance ![]()
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#75 |
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![]() Join Date: Jul 2018
Location: Little River, SC
Posts: 105
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Re: What GM create engine to buy for 3/4 ton 72 C20
I just dropped a crate 350 from advance auto. 4 year warranty for $1700. They also offered a performance version for 2700 but only had a 1 year warranty.
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