Preparing to Build! (Check my work...)

[scottofksu]

I am collecting parts to rebuild the 350 (soon to be 383) that will go into my 1965 C10 short bed. Below is my recipe; please, let me know if I am missing anything!

Machine Shop Trip #1
Clean Block
Magniflux/Inspect for cracks I missed
Bore as little as is necessary
Deck-plate hone
.00 Deck the block for use with a .038 gasket (was going to run quench/squish down to .030, but I chickened out)
Measure crank, mains, and rods for bearings

Home
Clean out machining grit
Paint

Machine Shop Trip #2
Install Cam Bearings
Press fit pistons
Install Freeze and other block plugs
File Fit Rings

Parts
1974 4-bolt GMC block
SCAT 3.75 Crank
SCAT 5.7" Stock Replacement Forged Rods
+12cc Dish pistons (H859CP30)
Lunati 276/284 Cam (@50 = 233/241, .504/.525, intake opens at 68 degrees)
Vortec Heads (exhaust ported and polished, intake and chambers cleaned up. Screw in studs and the LS6 behive springs (26981-16), new valves with 20 degree back-cut, 3-4 angle valve job, 64cc)
HEI Distributor recurved for this engine
Edelbrock Air-Gap intake
Quick Fuel 780 CFM carb (HR-780-VS)

These parts result in a static compression ratio of 10.33, and a dynamic compression ratio of 7.90. Advancing my cam 1 degree gets me to a dynamic ratio of something like 7.98. I will probably run the cam "straight-up" unless I feel the engine is underpowered, in which case I will advance the cam 1 degree.

I will be running my SM420 to start, but will be upgrading to a TKO-600 as soon as possible... Gears will stay at 3.75 until I get the TKO, and then I may bump them to 4.11s.

Thanks for any advise you can provide!

[truckdude239]

i'd do all machine work at one time they can asht eh block after boring and milling better then you can at home. pls most machine shops have a long wait time

[scottofksu]

Originally Posted by truckdude239

i'd do all machine work at one time they can asht eh block after boring and milling better then you can at home. pls most machine shops have a long wait time

Thanks David!

My only concern was cleaning all of the honing debris out of the crosshatch before assemble. I plan to be pretty detailed in how clean I get the cylinders... Not sure if I could expect this level of detail from the machine shop... Therefore, I didn't want them to install my cam bearings before I had a chance to clean as I was afraid they'd start to rust before assemble. I am not in a huge hurry. Just wanting to get the truck running by fall.

[cg285]

you're afraid the cam bearings are going to rust?

[65Gregg]

You might need to research the cam and Vortec head combo, I think you'll need to open up the push rod slots with the increased lift.

[scottofksu]

Originally Posted by cg285

you're afraid the cam bearings are going to rust?

I've been warned that getting them wet is a no-no. I'll be using soapy water and brushes to clean the honing grit out of the cylinders. While I will be spraying all parts off with compressed air and then WD-40, I have heard that the cam bearings will still begin to rust if I get them even a little wet...

I forgot to mention, that I have enlarged the push-rod holes to 1/2 inch...

Thanks!

[cg285]

Originally Posted by scottofksu

I've been warned that getting them wet is a no-no. I'll be using soapy water and brushes to clean the honing grit out of the cylinders. While I will be spraying all parts off with compressed air and then WD-40, I have heard that the cam bearings will still begin to rust if I get them even a little wet...

I forgot to mention, that I have enlarged the push-rod holes to 1/2 inch...

Thanks!

water won't hurt anything. don't give it a second thought. i would advise to listen to your machinist guy instead of the internet guys

[geezer#99]

Have you bought any parts or is that just a wish list?

[GASoline71]

On the "2nd machine shop trip"... cam bearings require a special tool, but the other stuff can be done at home. The shop can hang the rods on the pistons for you, but thoise can be done at home as well. Even press fit piston pins.

Save you a little cash to do it yourself.

A good wiping of the bores with a clean, lint free cloth and some acetone is all that will be needed.

Gary

[scottofksu]

Originally Posted by geezer#99

Have you bought any parts or is that just a wish list?

I have rods, crank, block, and heads. I was going to wait to order the pistons until I see how far it needs bored.

Thanks for the tips, Gary and CG285!

[Captainfab]

Are you going to have the machine shop clearance the block for the 3.75" stroke or are you doing it? Are you planning on a small base circle cam? If not I would suggest going with the Scat 5.7" stroker rods. You will still have to check the rod to cam lobe clearance, and grind as needed.

[scottofksu]

Captain, you've highlighted some areas that I've been wondering about... I've read some reports of people getting by without running either a small base circle cam or modifying the block. I figured I'd check my clearances on my trial assembly and go from there. I've been going back and forth about ponying up the extra $75 to return my current rods for the cap screw/stroker rods...

[PGSigns]

One more thing that is out of order. You can not deck the block till you trial assemble the engine with the components being used and see what the deck height is. Boring the block needs to be done based on the pistons going in it for the final hone to set the clearance correctly. I wash my blocks after all machine work is done and clean all the passages. Then install all the cam bearings and plugs and wash it again. Soap and water will not hurt a thing. Dry block well and spray with wd40. I also use acitone to clean the cylinders and do a final wipe with marvel mystery oil.
Jimmy
Jimmy

[Econman]

Your valve guides will need to be machined down for that cam. And I bet a 650 carb would be big enough.

[BigEd36]

Good advice from these guys. The two additional things I'm seeing are:

When figuring the compression ratio I'm getting 10.31 static (vs your figure of 10.33), so we're agreeing there. But using the advertised durations of 276/284, LSA 110, ICL 106, I'm coming up with 64* ABDC for the intake valve closing point, which gives a dynamic CR of 8.33:1, definitely want a tight quench for that. Which leads to my 2nd suggestion: The pistons you've listed have a round dish that doesn't leave a good quench deck. Here's the pic of the piston from the Federal Mogul website:



I would suggest using a piston with a D deck/reverse dome type dish for a better quench. Like this KB197, it's also 12cc dish, but will give a much better quench/squish. The KB pistons are more costly, but they also have a 1.433 compression height, so you'll be able to deck .008" less off the decks. https://www.uempistons.com/index.php...roducts_id=489

[scottofksu]

Thanks Ed!

Man, I don't know how I messed up the intake valve closing point... Good Catch!
Will a more quench friendly pistons allow me to run dynamic compression at 8.33 and still use pump gas? I can't imagine it will...

To this end, will these pistons work:

http://www.northernautoparts.com/part/sl-h137cl30

Would it be useful to run the cam at 3-4 degrees retarded to get the dynamic compression down?

Thanks again one and all for the advise!

[msgdsrf]

Couple thoughts

You didn't mention line honing or if the deck honing will be plate torque.

Assembly balanced?

Also, 8.33 is pump friendly enough. Dish pistons are said to actually cause increased risk of predetonation. Possibly more than the slight decrease in compression. I'm just above 8.6 dcr with a similar setup though AFR 63cc heads, flat tops, running premium with 34 degrees total timing and 10 degree vacuum advance. My 8.6 is a little more than I would consider perfect though, 8.3 sounds perfect. Though you wold be using premium gas.

[scottofksu]

Originally Posted by msgdsrf

Couple thoughts

You didn't mention line honing or if the deck honing will be plate torque.

Assembly balanced?

Also, 8.33 is pump friendly enough. Dish pistons are said to actually cause increased risk of predetonation. Possibly more than the slight decrease in compression. I'm just above 8.6 dcr with a similar setup though AFR 63cc heads, flat tops, running premium with 34 degrees total timing and 10 degree vacuum advance. My 8.6 is a little more than I would consider perfect though, 8.3 sounds perfect. Though you wold be using premium gas.

Thanks for the feedback!
I do not intend to line hone... My understanding was that this is generally not entirely necessary and that it is debatable if it helps much (baring extremely out of spec mains).

I do intend to have a deck-plate used when honing.

I intend to externally balance the motor as I believe the crank I am using would require the addition of heavy metal to internally balance.

I don't mind running premium at all! I just want to be able to get gas when I need it without having to find stations carrying a specific octane fuel...

As an aside, I have spoken with Northern Parts and they will exchange my "stock replacement" rods for the "pro-comp/stroker" ones for $40. Even though I bought the parts off of Amazon, Steve at Northern has been AWESOME to work with!

[BigEd36]

Originally Posted by scottofksu

Thanks Ed!

Man, I don't know how I messed up the intake valve closing point... Good Catch!
Will a more quench friendly pistons allow me to run dynamic compression at 8.33 and still use pump gas? I can't imagine it will...

To this end, will these pistons work:

http://www.northernautoparts.com/part/sl-h137cl30

Would it be useful to run the cam at 3-4 degrees retarded to get the dynamic compression down?

Thanks again one and all for the advise!

These will sure work better than the round dish pistons, but I wonder why the point between the valves on these pistons looks like the end is lower than the top of the piston, not like a full point like the KB pistons. Looks like you would loose a little bit of the quench/squish. These are a little bit cheaper than the KB's, but they are a narrow ring piston so the rings will cost a little more. For my money, I would go with the KB's with the extra .008" compression height. Like msgdsrf said, built with a tight quench you should be ok with 8.33:1 dynamic CR, but it'll likely require premium grade gasoline.

[scottofksu]

Here are the modifications I am making/planning on making based on your feedback:
1. SCAT Pro-Comp Rods
2. KB-197 Pistons to promote quench/squish
3. Quick Fuel 680cfm Carb (HR-680-VS)

I will also be installing my freeze plugs and rings on my own...

I think that's it! Let me know if I've missed anything...

Otherwise, I will get back to you all in a month or so to let you know how it turned out!

Thanks again!

Scott

[Econman]

Don't forget that stock Vortec heads will only handle .470 max lift without modification. The valve guides must be cut down. Good luck with the build!

[scottofksu]

Originally Posted by Econman

Don't forget that stock Vortec heads will only handle .470 max lift without modification. The valve guides must be cut down. Good luck with the build!

Indeed! I should have mentioned... I intend to run the Comp Cams 26981's. I hear that these are good to .53 without doing any machining. I'm not counting on it. Once assembled, I intend to have the machine shop measure my maximum lift, and will respond to their findings accordingly. Thanks for the luck, I'll need it! Hopefully I'll be back with dyno numbers some time in the early Fall (want to do a chassis dyno to dial in the timing and fuel once the engine is installed and mated to my SM420).

[scottofksu]

Update:
Block, crank, rods, and pistons are at the machine shop! Taking in my flywheel to see if it's worth using, and ordering a damper. When it leaves I will have a square, decked, and cleaned block. Machinist did a great job acting impressed by my block grinding results (e.g. clearancing, improving oil drain back and pumping drags, and slag/sharp-edge removal)!

[GRX]

All this talk about quench/squish is good but full benefit will only be seen if some measurements are made and the block is zero decked to remove any out of square conditions in relation to the crank center line. Install your crank, rod/piston assemblies at the four outer corners, then measure piston depth at top of travel in each cylinder. Any differences? Of course, all that is dependent upon consistency of piston heights and conn rod center to center measurements. These are the things (among many others) which should be done when you want to enter the world of engine blueprinting. Each operation on it's own may not improve things much. Yet when all are added together it will be the difference between an engine which runs well, and one which truly performs.

[scottofksu]

Machine shop games!