What have you done to your square lately??

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

ChuckN

Full Access Member
Joined
Nov 8, 2022
Posts
2,082
Reaction score
7,636
Location
Bellinham, WA
First Name
Chad
Truck Year
1981
Truck Model
C10
Engine Size
350
Boo, haha. It is what it is. Just trying to make a case for both at this point.

I stopped by both the machinist and HRMC. The machinist spotted stuff that said would need a bore. And to meet my requirements for performance, a rotating assembly + block work would be very NOT cheap. Putting the new heads on a this engine as is would be a low compression slug in the 8s, (and it more or less feels that way already) and it wouldn’t have the displacement to use all the extra airflow unless I was wringing its neck all the time.

Paul at the shop has both SBCs in his cars as well as a LS swapped squarebody. His input is that the drivability of an LS worth it alone. He’s setting some time aside on Friday and bringing his truck to the shop to give me both the goods and the bads about what a guy or gal gets into with these swaps. We’ll see what happens.

A guy could show up locally with a 383 and I’d be just as excited about it if the price was right.
 

ChuckN

Full Access Member
Joined
Nov 8, 2022
Posts
2,082
Reaction score
7,636
Location
Bellinham, WA
First Name
Chad
Truck Year
1981
Truck Model
C10
Engine Size
350
If you are going to go to the work for a different engine family swap go lt1 or lt4. But in reality
You can do a fresh 383 build with pieces you mostly have. For less money than you will have in a swap with a used engine. My .02 I wasn't even looking for deals and this was 2 minutes if searching
You must be registered for see images attach
You must be registered for see images attach
That’s an option. Just depends on whatever else comes along with it. Block work to be gone through completely (and I’m not going forward without that) would be at least a grand locally.
 

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
9,940
Reaction score
19,069
Location
kansas
First Name
Rick
Truck Year
1975
Truck Model
c20
Engine Size
350
That’s an option. Just depends on whatever else comes along with it. Block work to be gone through completely (and I’m not going forward without that) would be at least a grand locally.
Seriously,to hot tank,bore,and install cam bearings?
 

bucket

Super Moderator
Staff member
Moderator
Joined
Aug 3, 2010
Posts
35,095
Reaction score
43,613
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
I dunno, the very mildly hopped up 327 moves my big ol Impala around just fine. With good aluminum heads and a few other things, it would be a real hoot.
 

ChuckN

Full Access Member
Joined
Nov 8, 2022
Posts
2,082
Reaction score
7,636
Location
Bellinham, WA
First Name
Chad
Truck Year
1981
Truck Model
C10
Engine Size
350
Seriously,to hot tank,bore,and install cam bearings?
And to deck the block. But it’s my suspicion that with that kit, you would have to clearance the block as well for crankshaft throws.

Yep, he quoted me 1000 to 1500. There’s one other place I can check, but I think locally that’s the going rate since there’s no competition.
 

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
9,940
Reaction score
19,069
Location
kansas
First Name
Rick
Truck Year
1975
Truck Model
c20
Engine Size
350
And to deck the block. But it’s my suspicion that with that kit, you would have to clearance the block as well for crankshaft throws.

Yep, he quoted me 1000 to 1500. There’s one other place I can check, but I think locally that’s the going rate since there’s no competition.
Were you going to deck the block before? Sure it's a good idea but your used ls engine isn't go to be decked or even have new cam bearings.
It's not right to compare all the bells and whistles 383 build with a pull it from a 19 year old junk car and install it build. Just remember you are comparing a mystery 19 year old used engine to a fresh build.
 
Last edited:

ChuckN

Full Access Member
Joined
Nov 8, 2022
Posts
2,082
Reaction score
7,636
Location
Bellinham, WA
First Name
Chad
Truck Year
1981
Truck Model
C10
Engine Size
350
Were you going to deck the block before? Sure it's a good idea but your used ls engine isn't go to be decked or even have new cam bearings.
It's not right to compare all the bells and whistles 383 build with a pull it from a 19 year old junk car and install it build. Just remember you are comparing a mystery 19 year old used engine to a fresh build.
I totally understand that.

Just talked to another machine shop, and he said 7-800 for complete block work. Decking? Well, I mention it because both shops mention it. It might not need it, you’re right. But I think this is one of those “hope for the best, prepare for the worst “ scenarios. Based on what the guy told me when I purchased it vs the condition now, we’ll, I wouldn’t be surprised.

I’ve got logistical fish to fry, either way. I have very limited garage space and getting a cherry picker is going to be challenging, and an engine stand…hoo boy.

I’m in the process of looking at stuff for the SBC, thanks for pointing out those links. One shop said Eagle stuff is usually pretty reasonable.
 

DoubleDingo

Full Access Member
Joined
Jul 3, 2012
Posts
13,900
Reaction score
23,748
Location
Right where I am
First Name
Bagoomba
Truck Year
1981
Truck Model
81-C20 Silverado Camper Special-TH400-4.10s
Engine Size
Carb'ed Vortec 350
I totally understand that.

Just talked to another machine shop, and he said 7-800 for complete block work. Decking? Well, I mention it because both shops mention it. It might not need it, you’re right. But I think this is one of those “hope for the best, prepare for the worst “ scenarios. Based on what the guy told me when I purchased it vs the condition now, we’ll, I wouldn’t be surprised.

I’ve got logistical fish to fry, either way. I have very limited garage space and getting a cherry picker is going to be challenging, and an engine stand…hoo boy.

I’m in the process of looking at stuff for the SBC, thanks for pointing out those links. One shop said Eagle stuff is usually pretty reasonable.
Weren't going to need a cherry picker and engine stand anyway?
 

xm20k

Runs on 93 octane, caffeine, and spite
Supporting Member
Joined
May 26, 2025
Posts
1,109
Reaction score
2,847
Location
Girard, Ohio
First Name
David
Truck Year
78
Truck Model
c10
Engine Size
388
Have it punched to 4.060 and make it into a 388. I would also just have them cleanup the deck surface and not knock it down to 9" with a small chamber and thin gasket should be in the 9.5-9.75 CR range with the 2 valve relief flat tops. Will make more than enough torque to get in trouble with.

 
Last edited:

ChuckN

Full Access Member
Joined
Nov 8, 2022
Posts
2,082
Reaction score
7,636
Location
Bellinham, WA
First Name
Chad
Truck Year
1981
Truck Model
C10
Engine Size
350
Have it punched to 4.060 and make it into a 388. I would also just have them cleanup the deck surface and not knock it down to 9" with a small chamber and thin gasket should be in the 9.5-9.75 CR range with the 2 valve relief flat tops. Will make more than enough torque to get in trouble with.

Thanks for that suggestion- I may have been incorrectly thinking that a standard 350 block would have to be clearanced for the bigger crank?

Sorry that my posting hijacked this thread today, wasn’t my intention @everyone.
 

legopnuematic

Licensed Junk Dealer
Supporting Member
Joined
Oct 27, 2016
Posts
5,135
Reaction score
19,120
Location
MO
First Name
Spencer
Truck Year
1971, 1̶9̶7̶4, 1976, 1979,1̶9̶8̶5, 2002
Truck Model
Dart Swinger, Sierra 10, C10 Cheyenne, C10 Big Ten, Silverado 10, Ram 2500
Engine Size
225/6, 350 c.i., 350 c.i., 5.9l Cummins
@ChuckN I’ll echo some of what others have said, don’t jump ship yet on what’s in the truck now.

Clean the deck surfaces up and take some basic measurements to determine where things are at and see what you have to work with. I’d have a hard time believing the compression would be that low with flat top (4 valve relief) pistons, the 461 heads should be around 64CC chambers, unless if it was rebuilt using super short rebuilders pistons, not decked, with a super thick head gasket.

A stock 70s smogger 350 should blueprint to around 8.5:1, with dished pistons, 76cc chambered heads, etc etc.

The bores might not look great, but if it ran well, didn’t have excessive blowby, smoke, make oil, or lose oil, I personally wouldn’t be above overlooking some things.

I suppose it does boil down to what you want from it as a result, if you are dead set on not building a 327, I’d put it back together with the old parts, then you can continue to enjoy it, find a good 350, maybe a factory roller block w/mech fuel pump provision, that’s still a 350, go through it, put your go fast goodies on it, get it ready to go, swap them, put the old mill up for sale. I’m sure that someone would want a running “327” for their traditional hot rod/t bucket/whatever.

Having something that in some capacity runs and drives is more fun than having something blown apart for months. BTDT.

Just my 2¢ for free.
 

Latest posts

Forum statistics

Threads
48,401
Posts
1,066,562
Members
42,779
Latest member
blue10
Top