350 GM Crate Motor questions for a 66 C10

[geezer#99]

Quadrajet is fine but you need to watch the pressure output on the electric pump. Safest to use one with a max of 5 psi. Then if you change carbs in the future you’re covered on pressure. Edelbrock for instance are pressure sensitive.
And to make your electric pump happy you might need a return line to the tank. They don’t like to be deadheaded and can overheat. A return style regulator helps for that.

If you use your quadrajet with a square bore intake you’ll need an adaptor too.

Everything’s adding up. It’s the snowball effect.
With all the extra parts needed to use the L31 then the 195 hp 350 starts looking pretty tempting.

[WorkinLonghorn]

Everything’s adding up. It’s the snowball effect.
With all the extra parts needed to use the L31 then the 195 hp 350 starts looking pretty tempting.

Geezer#99

That was my conclusion. I bought the 195 HP new crate and it goes in this week.

[msg]

Originally Posted by geezer#99

And to make your electric pump happy you might need a return line to the tank. They don’t like to be deadheaded and can overheat. A return style regulator helps for that.

Ill call Summit today and see if they can put some options together for me on this, thanks for mentioning

Originally Posted by geezer#99

If you use your quadrajet with a square bore intake you’ll need an adaptor too.

I thought the intakes I posted links for were square bored, shouldnt they work without an adaptor?

Originally Posted by geezer#99

Everything’s adding up. ... the 195 hp 350 starts looking pretty tempting.

It sure is.

[msg]

Originally Posted by WorkinLonghorn

Geezer#99

That was my conclusion. I bought the 195 HP new crate and it goes in this week.

Let us know how it goes. The one thing that my friend who is helping me mentioned was the break in was a crucial step and with my carb being parked for years put extra concern on whether the engine could stay running at first crank so things dont go wrong with the flat tappet cam and all. My luck lately hasnt been so hot, so Im not ruling out the L31 just yet.

I did get a bit spooked with some of the reviews I saw at Summit on that L31. Timing chains mistoothed, and the warranty I will need to watch for. I think the buy date and the install/crank/run date need to be close together.

https://www.summitracing.com/parts/nal-12681432

[garyd1961]

9

Originally Posted by msg

I am coming around to the L31 everyone is suggesting if this stays in the $500 ballpark in additional parts and doesnt make things really difficult to install.



$163 (if I have the right part here)
https://www.summitracing.com/parts/sum-226018/reviews/




$61 (if I have the right part here)
https://www.summitracing.com/parts/s...0sfi/overview/



I searched on Summits site but really dont know what version I would need. Ill call tomorrow and get some help, but $50 to $90 was what i saw.
https://www.summitracing.com/parts/hly-12-427




On this I need to take some measurements before I can get a part to order. Ill look for the distributor I took off and measure what they need.

Summits items list there is around $300


In contrast I called the Jegs tech tonight and got these as parts. Around $500, but that edlebrock intake did the most damage.

The engine itself was the cheapest
https://www.jegs.com/i/Chevrolet-Per...81432/10002/-1

Electric Fuel pump
$105
https://www.jegs.com/i/Holley/510/12-930/10002/-1

Intake
$252
https://www.jegs.com/i/Edelbrock/350/2716/10002/-1

Flexplate
$117
https://www.jegs.com/i/B-M/130/20239/10002/-1


The other thing I am looking at is the exhaust. The headers I had on the 350 were rusty but working. Not sure if they will fit the L31. If not I'll be looking for a new set...or just buy more stock manifolds instead.

The flexplate you posted here is for a 2 piece rear seal internally balanced. You need one for a 1 piece rear main seal externally balanced.
Get the mighty-mite 12- 427. It will work for a carb, been running one for 2 years or more.
I'm not saying the 195 hp is a bad motor but the L31 Vortec is the most technically advanced sbc ever built. It has the old 195 hp motor beat in almost every category. To start with you get 100 more hp and way more torque. You can run the L31 for 300,000 miles with very little wear to the cylinders. You don't have to worry about a flat tappet cam losing a lobe. No 2 piece rear main seal to leak.
For the money you get a whole lot more with the L31.
It looks like they have more versions of.the mighty mite since I bought mine. What you want is the 12-427 4-7 psi good for 400 hp.

[msg]

I called the Summit tech line and told them I was swapping out a 350 from 1975 to the Chevrolet Performance 12681432 L31 and here is what I was told.

Intake Manifold- Gave me the edelbrock at $232
https://www.summitracing.com/parts/edl-7116
and Summit model. He mentioned I would need the Square Bore Manifold to Spread Bore Carb plate also and gave me this item number..$35
https://www.summitracing.com/parts/trd-2109/overview/

Electric Fuel Pump- He said there were a huge list of them to choose from, I mentioned the one Gary mentioned and he said that would have been a first choice for him as well -$45

https://www.summitracing.com/parts/hly-12-427/overview/

He also mentioned mounting it as close to the tank which for me is in the cab. Then he talked about there could be alot of additional things like the filter and probably a bunch of other parts that would likely be involved...and that the shop I have do it would be the ones to tell me. But with this being done in my garage I hope there are some quality and accurate how to's out there and a list of what to gets or I might mess things up.

Flexplate- he said it wasnt needed. I asked are you sure? He said yes the L31 isnt the LS engines that would have been from the year 2000 onward.

Melonized gear- he said it wasnt needed. I tried measuring the dist shaft that I took off the engine and Im not sure Im measuring the right spot. He said as long as its .5 inch it will work, but .8730 is what the caliper reads if I measure the outer diameter of the end of the shaft. The inner diameter portion is .49

[geezer#99]

You don’t want the electric pump in the cab. The noise will make you pull out all your hair.
Below the tank on the frame rail works.
You do need a different flexplate. The one piece rear seal is different than the two piece.
You may or may not need a melonized gear. You should ask gmperformance that question.
You do realize installing either motor yourself and not at a authorized shop might void the warranty.

[msg]

Originally Posted by geezer#99

You do realize installing either motor yourself and not at a authorized shop might void the warranty.

Thanks, I will check with Summit on this but the warranty link on that page for the motor has this included in the warranty write up. I had a 350, not sure if its considered a direct replacement.

"GM Goodwrench engines installed as direct replacements in a car or light truck application are warrantied for 36 months or 100,000 miles from the time of purchase, whichever comes first. This warranty is the same regardless of who installed the engine."

[garyd1961]

Whoever you talked to doesn't know squat about a L31 swap.
You do need a new flexplate, I went with the SFI just as an upgrade but you may want to go with a factory style flexplate. I had to drill the bolt holes in my converter to a larger size, not a real problem though.
Pick your carburator before you buy an intake. They come in square bore for holley type carbs and spread bore for Quadrajet type carbs. I recommend a new carb no matter what. No need to put a junk carb on a new motor.
You can mount your fuel pump on the frame anywhere between the tank and motor. I would keep it lower than the tank though.
You do need a melonized gear(not melonite coated). The distributor shaft for a stock HEI is smaller than MSD pro billet. The pro billet has an .50 inch shaft not sure the size of the factory shaft but it's the smaller one.
As for the warranty I don't know if it true but I read that you only have a 12 month warranty if you install it yourself but you are going to find a lot of small print restrictions with all warranties. It would cost you as much as a new motor to get a dealer to install it anyway so you might as well do it yourself.
I don't know if anyone mentioned it yet but you will also need a new dipstick and tube. I just found one to fit the block, cut it to the length I wanted, dumped five quarts of oil in the motor started it up, shut it down and marked my dipstick to the level.

[geezer#99]

Isn’t there also a need for a timing cover change or timing pointer set up.
And possibly a fuel pump boss cover plate.

[Captainfab]

I agree with garyd1961. Who ever you talked to doesn't know what is needed for a L31 Vortec. Yes you absolutely do need a melonized distributor gear. If you do not, you will eat up the gear on the roller cam. And yes you will need a new flexplate for the 1pc rear main seal. If the budget is an issue, why are you looking at new Edlebrock intakes? Why not look at the Summit or Jegs private label intakes. That will same you some money. The timing cover may or may not need changed. It depends on what water pump is being used. The crank sensor hole will need to be plugged with either a sensor or a metal plug made for doing so. No need for a fuel pump blockoff plate.

[msg]

Originally Posted by garyd1961

You do need a new flexplate, I went with the SFI just as an upgrade but you may want to go with a factory style flexplate. I had to drill the bolt holes in my converter to a larger size, not a real problem though.

For the L31, which bolt pattern should I be looking for on the flexplate without having to drill holes? Is it Dual Bolt Pattern like this?

https://www.jegs.com/i/JEGS/555/601074/10002/-1

Originally Posted by garyd1961

No need to put a junk carb on a new motor.

Only need for me is to save some dough, really hoping to reuse the carb for now.

Originally Posted by garyd1961

You can mount your fuel pump on the frame anywhere between the tank and motor. I would keep it lower than the tank though.

I think the way I typed it earlier reads wrong, he was just suggesting that it be mounted closest to the tank as I can. My tank is in the cab so just like you said on the frame should be where its mounted.

Originally Posted by garyd1961

You do need a melonized gear(not melonite coated). The distributor shaft for a stock HEI is smaller than MSD pro billet. The pro billet has an .50 inch shaft not sure the size of the factory shaft but it's the smaller one.

I dont think my HEI is stock, Ill get some pics and post tomorrow.

Originally Posted by garyd1961

I don't know if anyone mentioned it yet but you will also need a new dipstick and tube. I just found one to fit the block, cut it to the length I wanted, dumped five quarts of oil in the motor started it up, shut it down and marked my dipstick to the level.

This is the first Ive heard, hopefully its as easy as your write up reads.

Originally Posted by Captainfab

If the budget is an issue, why are you looking at new Edlebrock intakes? Why not look at the Summit or Jegs private label intakes. That will same you some money.

I am really hoping to save where I can but after watching this comparison video I wonder if spending the extra $90 would be worth it for USA quality?

https://www.youtube.com/watch?v=ATld...rr_watch_on_yt

Originally Posted by Captainfab

The timing cover may or may not need changed. It depends on what water pump is being used.

The water pump I have is a long pump, would that require a timing cover change?

Originally Posted by Captainfab

The crank sensor hole will need to be plugged with either a sensor or a metal plug made for doing so. No need for a fuel pump blockoff plate.

A plug sounds cheaper than a sensor to me. Ill have to look around for parts to price on that.

[95 S_Trucker]

Originally Posted by msg

Thanks, I will check with Summit on this but the warranty link on that page for the motor has this included in the warranty write up. I had a 350, not sure if its considered a direct replacement.

"GM Goodwrench engines installed as direct replacements in a car or light truck application are warrantied for 36 months or 100,000 miles from the time of purchase, whichever comes first. This warranty is the same regardless of who installed the engine."

A direct replacement means taking out an L31, and installing an L31. That warranty only apllies to 96-02 vehicles where the engine is installed by a shop or dealership.


If you bought an engine and installed it yourself, it would have a 30 day warranty.

If a shop or dealership installs the engine, it would have a 24 month/50,000 mile warranty.



Look at the bottom chart on the second page here:

https://static.speedwaymotors.com/pd...87warranty.pdf

[Jrainman]

There are a lot of things you will need to order mI have done this swap but with a L31 HD version not the L31 that has been posted , yes Melonized gear you will need no issues with your HEI distibutor, yes on the plug for the timing cover ,you will need a intake gasket but get the felpro kit that comes with new valve cover gaskets you will have to remove at least one valve cover to bolt your intake on ,so get rid of the stock cork valve covers and replace them with the upgraded felpro , I would weigh the cost between keepin the V belt or going to a junk yard and pulling a complete serp belt system off a vortec, It was cheeper for me to go the junk yard and pull it all ,including alt,PS pump, AC comp, and fan clutch and just clean paint and bolt it rite up, with no alignment issues trying to use the old v belt system , long water pump or short depending on V or serp, you will need oil filter housing , and yes a Flex plate with new flex plate bolts , also oil dip stick and valve cover breather orings and pvc valve, breather cap , and also exhaust manifold gaskets , T/stat hoses for the water pump rad, heat and bypass , I am sure I am forgetting stuff but just trying to give you a picture of all the little goodies you will need for the L31

[msg]

Bummed on the warranty but not shocked. Thanks S_Trucker for posting that. Even if I could afford to have a dealership do the install I wouldnt be able to with the shape things are in. Just a cab on a frame so far with replaced stock suspension. The next step was to get the motor in and learn how to run all the lines that Ill be replacing. So things are on pause until I can decide with my time and wallet and the info and guidance you are all providing.

[msg]

I have purchased the L31 and its on its way. Ive also bought a good many other things to go along with the build.

Melonized gear
https://www.summitracing.com/parts/CCA-412M

Intake
https://www.summitracing.com/parts/EDL-2116

Electric Fuel pump
https://www.summitracing.com/parts/HLY-12-427

Flexplate
https://www.summitracing.com/parts/SUM-G104SFI

I spoke with American Autowire and explained what I was up to. They recommended this kit

Wiring harness
https://www.summitracing.com/parts/aww-500560

I was told that I will need to change out my alternator for an internally regulating alternator so thats a part Ill be looking for. I will be installing the Vintage Air sure fit system in the future so the compressor is planned for the passenger side. I have a long water pump and all the v style pulleys and brackets that were on my 350, but if going serpentine makes more sense I can check out the local scrap yards for all the pump pulleys and what nots but needed some help with what to look for years models etc. Im also looking for the honda civic coupe door weatherstripping ive heard good things about so Ill be there anyway.

Looking forward to seeing things progress. Been like this for a while now.

[Captainfab]

You won't be disappointed with the L31 engine. It's too late now but the AC Delco melonized gear is about $34.00 instead of $81.00 for the Comp Cams gear.

[msg]

Originally Posted by Captainfab

You won't be disappointed with the L31 engine. It's too late now but the AC Delco melonized gear is about $34.00 instead of $81.00 for the Comp Cams gear.

It may not be too late, I could return it. Is there a part # you can share for what Id need?

[Captainfab]

When you click on the link you posted, this pops up on the side as other items you may like.

https://www.summitracing.com/parts/a...6413?rrec=true

Originally Posted by msg

It may not be too late, I could return it. Is there a part # you can share for what Id need?

[msg]

Thanks Capt, Ill have to pay more attention or pay more money.

[Scott Liggett]

Wow. That is a lot of stuff to buy in order to get a GM stock replacement Vortec engine into a 66 C10.

And yes, please read their warranty. Those L31's full warranty applies to those being installed as a stock replacement engine, as in a truck that had an L31 to begin with. Otherwise, they go down to 12 months. So, please be sure before you purchase.

Have you looked at other options for engines?

https://www.summitracing.com/parts/m...ctc1/overview/

Has more HP, has nearly everything you need. Will take a mechanical fuel pump. They come with a 30 mo/50,000 mile warranty if you install or a shop does. And, now they are building them with roller camshafts.

Here is a bunch of different dress options on their roller cam/vortec head 350's.

https://www.summitracing.com/search/...ord=bp3503ctc1

[garyd1961]

If you check on the internet you will find a few horror stories about BP engines and their warranty.

[Scott Liggett]

Originally Posted by garyd1961

If you check on the internet you will find a few horror stories about BP engines and their warranty.

I think if you read a little farther than the first post, you will see they take care of their customers every time.

[msg]

Originally Posted by Scott Liggett

Wow. That is a lot of stuff to buy in order to get a GM stock replacement Vortec engine into a 66 C10.

And yes, please read their warranty. Those L31's full warranty applies to those being installed as a stock replacement engine, as in a truck that had an L31 to begin with. Otherwise, they go down to 12 months. So, please be sure before you purchase.

Have you looked at other options for engines?

https://www.summitracing.com/parts/m...ctc1/overview/

Has more HP, has nearly everything you need. Will take a mechanical fuel pump. They come with a 30 mo/50,000 mile warranty if you install or a shop does. And, now they are building them with roller camshafts.

Here is a bunch of different dress options on their roller cam/vortec head 350's.

https://www.summitracing.com/search/...ord=bp3503ctc1

Thanks for the input Scott, I already pulled the trigger though. In fact its scheduled to be delivered today! I looked at BP after the call I had to Summit that day I mentioned in post #31 and the tech guy pitched BP and said what he has experienced with customer and issues they have had. He spoke very highly of the reputation they have of making good. I hope I dont have any issues cause Ill be hosed on this deal. No warranty really for me to put the engine in. The total I have so far on the replacement is close to $2500 by reusing the distributor and carb I have. I hope the extra $1500 I'm not spending works out.

[msg]

On the fuel lines I was planning to get a brake line flaring kit and bend things myself. I was looking to buy the right fuel line size and type to bend and any extra fittings I may need. Is this the right stuff and size to use?

https://www.amazon.com/Nickel-Copper...ef_=ast_bbp_dp


and as I read back through the thread here I recalled this...

Originally Posted by geezer#99

And to make your electric pump happy you might need a return line to the tank. They don’t like to be deadheaded and can overheat. A return style regulator helps for that.

I did get the holley fuel pump that was recommended, you think its best then to do a return line and get a regulator? If so which regulator would do the trick?