New engine advice for the Farm Truck

[tim_mc]

My '67 farm truck is a combination of a '67 C20 cab, clip and bed mated to a C10 frame & drivetrain that had a running 350 Goodwrench crate motor with an Edelbrock intake and carb. Everything is new or rebuilt except the engine. It's built to be a daily driver with A/C & 4-wheel disc brakes and I drive it every chance I get. Since the original 350 ran before building the truck I decided to use it to help with the budget. Well, last week I drove to my cousin's house to get a spare driveshaft for my upcoming TH350 to 700R4 swap, and on my way home I started to get a "tick" that quickly became a louder "thunk thunk thunk" when under a load. It doesn't make much noise at idle or when revving with no load. I figure that I either lost a cam lobe, or have a bearing going out. Either way, the ultimate plan was to drop in a fresh 350 with a mild cam in the future. I'm not interested in an LS conversion and prefer to keep the nostalgic set-up. While I wish I had gotten more miles from the PO's 350, the timing of its demise is OK since I can now plan on yanking the engine and trans together instead of just swapping the transmission. My shortened drive shaft should be ready tomorrow from my local Inland Truck Parts, so I'm now focused on lining up a motor. I prefer new components over a reman unit. I want a budget friendly, dependable, mild cam motor with good torque. Existing exhaust is stainless long tube headers to a 2-1/2" dual exhaust with 2" H-pipe.
After searching on-line for a good crate motor and crunching numbers on a spreadsheet, I think I've narrowed it down to one of these two options:

Option 1: About $3400 in parts, including harmonic balancer, flexplate, new HEI distributor, etc.
- GM 350 long block, 12681429, 195HP, 4-bolt main, 8.5:1 comp., 76cc heads.
- Comp Cams Xtreme Energy Hydralic Roller Cam & Lifter Kit K12-408-8.
- Edelbrock Performer RPM Dual Plane Intake Manifold, 7101.
The GM longblock is made with all new components. This set up would use the stock heads, but improve the cam profile from:
.390/.410 int/exh lift, 195/202 int/exh duration at 0.50 lift, and 112 LSA to:
.480/.487 int/exh lift, 206/212 int/exh duration at 0.50 lift, and 110 LSA.
Comp Cams states that it's good for torque and mileage, stock to mild mods. The retro roller cam kit would hopefully give me more longevity over a flat tappet cam along with better HP.

Option 2: About $4200 in parts, including harmonic balancer, flexplate, new HEI distributor, etc. Same block and cam kit as above.
- GM 350 long block, 12681429, 195HP, 4-bolt main, 8.5:1 comp., 76cc heads.
- Comp Cams Xtreme Energy Hydralic Roller Cam & Lifter Kit K12-408-8.
- GM Vortec Cylinder Heads, 12558060, 64cc, 170cc runners.
- Edelbrock Performer RPM Dual Plane Vortec Intake Manifold, 7116.
Option 2 changes out the stock heads for better flowing Vortec heads. Using an on-line compression estimator, the compression ratio jumps from 8.5:1 to about 9.6:1 when dropping the combustion chamber down to 64cc.

I'm leaning towards Option 2, which gives me an old school 4-bolt short block with newer Vortec heads & roller cam up top. I'll likely get the 350 long block from Chevy dealer Cable-Dahmer in Independence, MO ($1849 w/free shipping). It's been 20 years since I've torn into an engine, so I'm calling a local builder tomorrow for the cost to check and assemble the components. Otherwise, let the gearhead re-education begin. I'm hoping there are a few master mechanics that might take a look at my plan and offer up any advice.
Thanks in advance!
~Tim

[tdangle]

You will also need a couple of things, a different drive gear for the HEI, and if you go option 2 valve covers and different bolts for manifold, carb, self aligning rocker arms. I would go option 2. I just installed GM SP350/357 deluxe crate motor. It pretty much came with everything but I still spent almost another $1000 on parts and exhaust system. It has a little more cam than you are looking at 215 intake 223 exhaust at .050 with 108 LSA. Tons of power but idle has a noticeable lope.

[RustyPile]

Are you sure it isn't a cracked flex plate or loose or cracked balancer, or something else making the knocking sound???.. Guessing and throwing parts isn't an approved diagnostic procedure..

[tdangle]

Sounds to me he really would like a new engine.

[tim_mc]

Originally Posted by tdangle

Sounds to me he really would like a new engine.

Yep! You got it Terry! Your advice on another post helped steer me away from the SP350. I used it's cam specs to narrow down what I wanted. I included a new distributor gear in the parts list. I'll make sure to add the rockers.

Edit: Added to the parts list - Comp Cams 1412-16 steel roller tip rocker arms, 1.52 ratio. These are recommended for the cam & lifter kit. Here are a couple of links for anyone interested in adding a roller cam to an older SBC:
http://www.cpgnation.com/roll-with-i...to-a-roller/3/
http://www.superchevy.com/how-to/148...lic-roller-cam

The sound seems like it's coming from a cylinder on the LH side and out the exhaust. I pulled the valve cover off and the rockers are all tight, so no broken rockers but I haven't yet bumped it over to see if they are still moving as high as they should.

[tim_mc]

I should have consulted with my cousin sooner. He's a machinist and has been building engines most of his life. He suggested that I switch out the GM cast iron Vortec heads to aluminum heads. While the heads are more per pair, I'll save $50 on the intake manifold cost, and won't need new Vortec valve covers. The aluminum heads have screw-in studs, 2.08" intake/1.6" exhaust valves, so that's a plus. And, I can reuse my OEM LT-1 valve covers in the pic.

[tdangle]

Sounds like a solid plan. I’m glad my posts were of help to you. Good luck with your build

[Mike C]

I'd have your original 350 machined, use an Eagle internally balanced two piece seal 383 kit from Competition products (about $750) then add cam, aluminum heads etc.

Your cam swap kills the warranty on the GM moror, why pay the premium and not get more displacement.

[tim_mc]

Thanks Mike...that gives me something to think about.

[tdangle]

Double check the warranty on a new gm crate motor. Unless installed in certain vehicles by an authorized dealer it is not what you think.

[tim_mc]

Originally Posted by tdangle

Double check the warranty on a new gm crate motor. Unless installed in certain vehicles by an authorized dealer it is not what you think.

Understood. I'm not counting on the GM warranty since I'll be installing it myself and it's a '67 - maybe too old for GM to cover. I was referring about Mike's comment for me to reuse my block and stroke it to a 383. I'm checking out the reviews and questions about Eagle Street Performance Rotating Assemblies B13405E030, $745.

I've looked at some reman short blocks, but the lack of many good reviews along with a couple of bad ones still has me leaning to a new GM block. New ZZ4 short blocks are going for $2400. Based on that, $1849 seems like a reasonable price for a new GM 4-bolt block with new crank, rods & pistons ready to go.

[tim_mc]

Update: I went with Brodix 70cc IK 180 aluminum heads complete with heavier valve springs for a roller cam (p/n 1021003). This is a 6cc drop over the stock Chevy 76cc iron heads which should push the compression to about 9:1. 2.02 intake/1.60 exhaust valves. Made in Mena, AR. They look great. The Chevy crate engine was delivered today to my local shop for the new roller cam conversion. Comp Cams is out of the cam I ordered, but they are just down the road in Memphis/Olive Branch, so I hope to get it next week. I'll probably swap the heads and install everything else myself now that I've had time to get reacquainted with building an SBC. I picked up another engine stand since the other stands at my dad's shop are occupied. After watching a video by Eric the Car Guy, I feel I could have set the cam end play myself:
https://www.youtube.com/watch?v=ui6vl28Ehj8

The crate motor is from Mexico, but at least the aluminum top end is from the USA.
Final Option:
- GM 350 long block, 195HP, 4-bolt main, 12681429.
- Comp Cams Xtreme Energy Hydraulic Roller Cam & Lifter Kit, K12-408-8 (.480 int/.487 exh lift, 206 int/212 exh duration @ 0.50 lift, 110 LSA).
- Brodix IK 180 aluminum heads, 70cc chambers, 180cc runners, 1021003.
- Comp Cams Magnum steel roller tip rockers & push rods, 1.52 ratio; 7.266" rods, RPR200.
- Edelbrock Performer EPS intake, dual plane, 2701.
- ACDelco HEI with melonized steel drive gear & vacuum advance, 93440806.
Fel-Pro gaskets, Manley head bolts & washers, etc.

I also picked up my drive shaft from Inland Truck Parts for the 700R4. They did a good job of shortening the drive shaft, installing the new U-joints and carrier bearing and repainted it.

[Ironangel]

Your going to "probably" need a new flex plate because it sounds like you've cracked the one on the motor coming out...? "Jus Sayin"

[tim_mc]

Ha! A flex plate is saved in the ol' Summit Wish List just in case.

[toolboxchev]

Option #3

Have you considered the L31 HD assembly from GM? Take that assembly, drill out the fuel pump, add the appropriate cam, Good to go up too 4500 rpm.

It sure does take lots of work out of it. Unless you looking for High Horsepower. Me I love my old school engine built for torque and geared that way also.

I do like the stock stuff, It performed quite well for 38 years before I came into possession.

Gen 1 350's are cool, anywhere from 295 hp to 375 from the factory, I believe they were very durable.


If your still looking to go old school take a good look at these made by Trick Flow: https://www.trickflow.com/search/pro...t?autoview=SKU

I might change your mind on some stuff. They even have the Heat Cross over for faster warmups and around town drive ability.

[toolboxchev]

edit duplicate

[toolboxchev]

Option #3

Have you considered the L31 HD assembly from GM? Take that assembly, drill out the fuel pump, add the appropriate cam, Good to go up too 4500 rpm.

It sure does take lots of work out of it. Unless you looking for High Horsepower. Me I love my old school engine built for torque and geared that way also.

I do like the stock stuff, It performed quite well for 38 years before I came into possession.

Gen 1 350's are cool, anywhere from 295 hp to 375 from the factory, I believe they were very durable.

[tim_mc]

Thanks Toolbox...the L31 would have been a great option, and even a bit easier with an electric low pressure fuel pump. I already pulled the trigger on the Gen 1 long block with aluminum heads. All of the parts are here except for the retro cam & lifter kit. Assembling the engine will be a welcomed distraction.

[BCOWANWHEELS]

find a doner vehicle.................. your spending too much for what. or reman what u got

[tim_mc]

The truck is back on the road! I've already used it to deliver a dirt bike and pick up some new shrubs for the front yard. My wife and brother convinced me to run it with the original stake sides.

Along with the new engine, I also added a 700R4 with hydraulic lock-up kit (no electric solenoid) and stock stall converter. Rear end gears are 3.08s, so I can easily cruise at 70+ at just under 2000RPM. The lower 1st gear in the 700R4 is great for local driving. The full headers with Magnaflows sound great when I step on it.

I'm currently tinkering with the new Edelbrock AVS2 1905 carb with annular flow primary boosters. The throttle response is better than the 600cfm Performer 1405 I was using on the old motor. I've got a good base set-up that runs great throughout the range in every gear. The only thing left to do is switch to next size smaller main jets (0.098) to see if I can squeeze a few more MPG without any lean surges when cruising.

It was a crazy April for me. I couldn't have done it without the help of my younger brother. We were on a shake down run and wound up at our grandparents house...seemed like a good place to take a pic.

[bigmac73]

Good info over at Hotrodder.com on the Roller tip rocker gimmick

https://www.hotrodders.com/forum/any...rm-184521.html

[BCOWANWHEELS]

there stronger, more accurate and the roller tip cant hurt. I,ve got comp 1.6,s on my new sbc. nascar and nhra racers run rollers for a reason fellas.

[bigmac73]

I believe in running full rollers with no doubt but in regards to those wanna be roller tips I also trust the input on the other forum as well

[tim_mc]

I hear ya. The roller tip rockers came in a package with the correct length pushrods for the retro roller cam set-up. I figured they were an upgrade to the OEM rockers. Ultra Pro full rollers would be nice, but these are good enough and were sure to fit under my LT-1 valve covers.

[bigmac73]

if it runs good and you are happy . Then that is all that matters
Enjoy and be safe