2022 Cost to Rebuild Engine Vs Crate Motor Vs LS Swap

G72Zed

Veteran Member
Sep 8, 2015
4,228
Canada
A destroked 400 to 377 is much better than a 400 build especially for auto cross that requires constant high RPMs. Using a 3.48 inch stroke and 6 inch rods will give you a 1.72 connecting rod ratio. Much better for high RPMs than the 400s 1.48 rod ratio and just shy of the 327s 1.75 rod ratio. There are a couple of benefits a 377 has to offer that have been lost in our current stroke everything modern hotrod mentality. Rod ratio is the biggest one. Not having the oil control ring going through the piston pin, being able to use big valves, and grinding down the combustion chambers giving the valves room to breathe in those big bores too. Use total seal rings and a oil separator/catch can for oil control. You’ll rev up much faster than any stroked combination and the engine will last longer too. I had a thought to add. A 3.25 stroke with a .030 overbore is 352. With 6.2 rods the rod ratio is 1.91. That’s nascar and Smokey Yunick territory.

I agree with pooch400 above^^^ , too much low rpm tq can bring up other issues, one of the reasons why I mentioned disconnecting the secondary link on my car a few times as an example, and I only had an all iron 333 cube but was making 540hp, pretty good with small 2.02 valves and cam under .500 lift. That combo had a 1.88 rod ratio.........

My current 362 cube sbc (4.060 x 3.50) has a rod ratio of 1.75, I like the combo, and it does have it's advantages, that's for sure. When I buy my next block, my first choice will be a 400 based 4.155 block with 350 mains, and still keep the 1.75 rod ratio. Just keeping the same hp per cube target goal will get me a reliable 567HP, don't even need a roller cam.


I originally wanted to do a 377, but from all the research I’ve done on 377 Vs 400, everyone says go for the 400, even the old 377 guys.

It kind of depends on the rest of the combo 9gear/tires/size of track), including the other engine parts all working together.

Yes, those larger bores really unshroud things, but that short stroke with that bore to stroke ratio (oversquared) and the natural rpm range, the valvetrain will need detailed attention. and, you start hitting over 575hp/tq, the stock block starts to do the flexy/funky chicken, even if only minute, it get's worse.

Lower rpm range/tq per cube/average lower end range with a stock block 400/3.75/6.00, the 406 works well.
 

G72Zed

Veteran Member
Sep 8, 2015
4,228
Canada
FWIW
400 w/ 6" rods --- plenty shelf piston choices where rod pin does not enter oil groove --- think metric ringpak.

*add
e.g.



When I worked with Mahle for my piston's, he was telling me they are changing all there higher end PP pistons to metric rings (1.0/1.0/2.0) said you will not even be able to get 1/16th anymore, no reason for N/A.

I like mine, same as above but 4.060.
 

Attachments

  • deck height.jpg
    deck height.jpg
    64.2 KB · Views: 38

sandlapper

Veteran Member
Oct 9, 2020
1,629
SE CSA
oh, that's sweet --- can even see a reflection of its eyebrows in its dish --- nice work!
those are some right pretty cockeyed jewels! 💓 I just love pretty motor parts!

yup, I verified the above 930210995 do Not have a wrist pin bore that intersects oil ring groove; therefore No support rails at play either. Only possible complaint is included top rings aren't steel; but they're a good ringpak regardless.
 

tom3

Veteran Member
Aug 1, 1999
14,908
ohio
Article in the recent Hot Rod magazine gave a full write up on rebuilding a one piece rear seal 350, vortecs, Summit parts internals, machine work. Expected 400 HP or better. Total cost with junk yard motor was $3700 or so. But we know HR's builds have a lot of screwy numbers too. Would be a bolt in swap. Not sure you can buy a crate or a used LS motor (especially with needed swap parts) for that money.
 

Chevyforever

Veteran Member
Jan 4, 2011
1,512
Canada
Article in the recent Hot Rod magazine gave a full write up on rebuilding a one piece rear seal 350, vortecs, Summit parts internals, machine work. Expected 400 HP or better. Total cost with junk yard motor was $3700 or so. But we know HR's builds have a lot of screwy numbers too. Would be a bolt in swap. Not sure you can buy a crate or a used LS motor (especially with needed swap parts) for that money.
I searched and couldn't find the build. any chance for a link ? thanks.

*** I found it, August 26/2022 author Jeff Smith.
 
Last edited:

sandiego74

Veteran Member
Lifetime Gold Member
Feb 23, 2009
1,189
San Diego, CA
Article in the recent Hot Rod magazine gave a full write up on rebuilding a one piece rear seal 350, vortecs, Summit parts internals, machine work. Expected 400 HP or better. Total cost with junk yard motor was $3700 or so. But we know HR's builds have a lot of screwy numbers too. Would be a bolt in swap. Not sure you can buy a crate or a used LS motor (especially with needed swap parts) for that money.
It’s a good reference for cost, but I also want to lighten up the front end.
 

sandlapper

Veteran Member
Oct 9, 2020
1,629
SE CSA
Shop work costs vary wildy across US --- get Your own estimates from shops You might use.
? Is it practical to have the auto machine shop work performed south of dago ? TJ ain't exactly third-world.

with all that's been said, I agree most with that guidance to take care of your family's shelter First.
Try to keep the car running; you might need to sell in order to best realize your growing family's needs.
 

sandiego74

Veteran Member
Lifetime Gold Member
Feb 23, 2009
1,189
San Diego, CA
Shop work costs vary wildy across US --- get Your own estimates from shops You might use.
? Is it practical to have the auto machine shop work performed south of dago ? TJ ain't exactly third-world.

with all that's been said, I agree most with that guidance to take care of your family's shelter First.
Try to keep the car running; you might need to sell in order to best realize your growing family's needs.
I know plenty of people down in Tijuana that probably know a reputable shop down there. I hadn’t thought of that. Thanks for the tips!
 




Latest posts

Top