Rebuild sbc 400 in K10 or Crate motor?

[2018GMC]

Putting a LS 6.0 and 4L80E in is very tempting but seems like a lot more work and I would be basically driving a GMT800 powertrain in a 1979 chassis.

[2018GMC]

1994Vmax offers some good advice. A junkyard LS will make 400 hp pretty easily and run very smooth, the bigger the LS, the easier the 400 comes. If you stick with your original small block 400 the key is getting the right cam, and better flow and the compression bumped up (mostly from the right heads), from there it all depends on where you want your power to start. The cam profile recommended would work well, keep your LSA in the 112 degree range, it will idle smoothly and you will make nice bottom to mid range torque which is what you want for a heavy vehicle. The HO 350 cam profile and similar grinds are good torque makers and places like Summit are good places to shop for stuff reasonably priced. If you want a lopey idle then a higher stall converter will be in order for an automatic trans and your power starts to move upstairs. Either the iron Vortec or Dart heads mentioned are very good power makers, both are much better than any other stock chevy iron head even from the 60's, but with the vortec heads it requires center bolt valve covers, special vortec bolt pattern intake, self aligning rocker arms and your lift is limited depending on who you talk to at around .480 + or -. They also have pressed in rocker arm studs. For not much more $$ I'd go the iron Eagle head route, you should be able to get an assembled set for around $900. With 64cc chambers and a stock bottom end with the pistons down in the holes a bit and dished pistons you should end up around 9.0 to 9.5:1 compression, do some bottom end work and get flat top pistons up at deck height and things get better. Hot Rod did a junkyard 350 a number of years ago where they yanked a 350 out of a 77 Impala (hardly performance oriented) didn't nothing to the engine other than bolt on parts, and got just over 400 HP using vortec heads, carb, intake, cam, headers, etc., none of it was anything special, so 400 HP is very realistic. If you feel the bottom end of your 400 is in good shape, bolt on the parts mentioned and have fun!

 

Thanks for the detailed reply. I will probably rebuild the entire engine. Who knows how many miles are truly on this old 400 and even though it runs ok now I don't want to cheap out on the bottom end to only pay for it later :-)

[2018GMC]

I would never...... ever buy a GMPP crate engine. A friend of mine owns an engine shop and I have personally got to tear down some that come in and just wow....... Junk. Failures are failures but these things are failing from just piss poor build quality. This goes all the way from your basic Goodwrench crate 350 up through the big blocks. Metal chips from not deburring, improperly installed main caps, valve seats ground crooked or falling out, piston to wall set to tight and scuffing etc. Very very poor workmanship, ill fitted parts and GM's warranty is utterly bogus. For the amount of money those things are to buy and all the fancy paperwork they show up with it sure doesn't mean much. I haven't seen an LS crate apart yet but I don't see how they would be any different. I have a crate L76 6 liter I sold to a friend but we are going to tear it down and measure it all before he ever runs it..... not to mention delete the afm and whatnot.

 

Build the 400 if you want to stay with a SBC as they are a fun engine. We put one together that ended up in a circle track car but it's a nice mild mannered engine that makes around the power you are after. It has basic Vortec heads on it, a marine spec'd hydraulic roller cam ( modest split duration... I think 218/224 on a 112 lsa) and 9.5:1 compression. The owner chose an aftermarket crank and rods for the build as he started with a bare block and forged pistons. The engine makes good torque honestly and great mid range power..... peters out just over 5 grand. The Dart Iron Eagle 165 S/S is basically a production Vortec head in a heavier duty casting with a normal intake manifold bolt pattern. But there are a thousand different opinions on a Gen 1 small block lol.

 

An LS would make more power though, run smoother doing it and be even more fun but it's all what you want. You can easily LS swap for your budget. A cam and headers equipped LQ4 will make the power you want..... plop on some 243 or 799 casting heads found off of every Gen IV 4.8 or 5.3 and bump the compression to 10.3:1 and have even more fun!

Thanks for the detailed response. It sounds like a dart head is the way to go if I want to use my Edelbrock performer intake and tall valve covers currently on stock 400. I do like how the older 350 / 400 make torque lower in the rpm range vs the LS motors. But the LS seems to pull hard up to 5800 where the 350 / 400 runs out of steam after 4400 or so. From my stock 79 400 and 97 350 experience.

[ifixedit]

When you get to the camshaft part, this one comes highly recommended. >>> http://www.summitracing.com/parts/hrs-112571-12?seid=srese1&gclid=CjwKEAiAvauyBRDwuYf3qNyXmW4SJACX9-fXEAr1Jyt-2ux79zCCMzrXySTYZQzb0ME-ktHvgR5jthoCMkTw_wcB

[Badass69]

Nowadays though with our oils that we have and use for dailies I wouldn't even look at a flat tappet cam. Rollers advantages were good enough even the El cheapo oems went that way across the board in the 80's

 

Sent from a potato

[ifixedit]

Nowadays though with our oils that we have and use for dailies I wouldn't even look at a flat tappet cam. Rollers advantages were good enough even the El cheapo oems went that way across the board in the 80's

 

Sent from a potato

True, you can go with retrofit roller lifters to avoid the flat tappet break in issue, but there's still plenty of oils out there like Valvoline VR1 providing the needed phosphorus to break in and use a flat tappet cam. Just broke in a flat tappet myself BUT maybe a roller next time around. ;-)

[Badass69]

It's not even just the lack of zinc... the ramp rate and lobe profile on roller make a flat tappet cam as modern as running a Ford flathead lol. The only reason the race team I sponsor runs flat tappet on some of the cars is sanctioning... otherwise that's not even a consideration. But then if we could we would run LS engines too lol.

 

Sent from a potato

[ifixedit]

It's not even just the lack of zinc... the ramp rate and lobe profile on roller make a flat tappet cam as modern as running a Ford flathead lol. The only reason the race team I sponsor runs flat tappet on some of the cars is sanctioning... otherwise that's not even a consideration. But then if we could we would run LS engines too lol.

 

Sent from a potato

 

I've read of a few gripes here and there on the modern ramp rates being a bit too aggressive and of failures due to this, but I would suspect most likely the problems are due to someone not doing things correctly in the first place. I decided to go flat tappet on my latest project as it was more or less a refresh than a rebuild and I couldn't justify the $700 (or more) just for the cam and retrofit roller lifters on this particular project. Gotta save it for a stall converter and better heads!

 

Now back to our regularly scheduled program.... Rebuild a sbc 400 or?

[2018GMC]

What do u all think about dropping this in?

 

Parting with my SBC 383 Stroker 475hp

Here's the parts list and specs:

Engine Specs

.030 1975 4-Bolt main 350ci *machine work done at Morrison in Glendale

Casting: 3970010

Scat 9000 crank 383 stroker w/ 6" Eagle Rods, ARP Fasteners, Balanced

Keith Black Hypereutectic 6cc Dome pistons w/ Plasmamoly file-fit rings

Comp Cam 12-678-4 .520/.540 244/252 solid lifter

Summit 1.6 roller rockers with +.100 hardened pushrods

Dart Iron Eagle 64cc, 2.02/1.6

Copper shim head gaskets

Double roller, steel timing chain/gears

High volume oil pump

10.3:1 compression

Edelbrock RPM Air Gap manifold

Aluminum tall valve covers

Aluminum oil pan

Aluminum timing cover

Fluid Damper SFI 400 balancer

New flexplate

ARP rod/head bolts

Proform electric water pump

Built and clearanced to Lingenfelter 383 specs

The motor as built in 2007. Has exactly 37 runs (1/4 mile). Sold the car in 2010, less motor and trans. Motor has been sitting in my garage since 2010, in hope of dropping it into another project. Though it has had the intake and exhaust ports taped/sealed, I would suggest freshening the bearings.

It is on a rolling, cradle engine stand, which I will include.

No carb or distributor.

This motor had a 7,000 rpm limiter.

Best ET in a 3200 lb. car w/TH350 and 4:27 gears 11.813 @ 113mph

I do not have to sell, so please no low ball offers.

I have well over $5,000 invested.

Will sell for $3,500 firm.

[2018GMC]

***Update***

 

Just ordered a new sbc 400 from www.blueprintengines.com

 

I thought about putting in a 700R4 but will probably just rebuild my Turbo 350 3 speed auto.

 

I will keep this updated when the engine is installed and running.

http://www.blueprintengines.com/index.php/products/bp-gm-crate-engines-landing/gm-400-main/item/gm-400-base-bp4001ct1

 

HP & Torque: 460 HP / 470 FT LBS

Compression Ratio: 10.3:1
Aluminum Heads
Hypereutectic Pistons
Roller Cam
Cast Steel Crank
Part #: BP4001CT1

Block:

BRAND NEW BluePrint Cast Iron Block
4 Bolt Mains
Square and parallel decked
Align honed main bearing bore
Cylinders are sonic tested for thickness
Cylinders honed on computer controlled machine to within .0002 straightness and roundness

1-Piece Rear Main Seal

Rotating Assembly:

New cast crankshaft
Cast 5.7" connecting rods
150,000 psi rod bolts
Hypereutectic pistons
Hastings moly rings
Rotating assembly balanced to within 2 grams
High volume oil pump
Hydraulic roller cam
Roller lifters

Cylinder Heads:

BluePrint aluminum — 64cc chamber
Hardened retainers and springs
2.02 swirl polished intake valves
1.60 swirl polished exhaust valves

BP Aluminum Head Part# H8002K
For complete head specs, click here

Cam Specs:

Cam Type: Roller
.544 Intake .555 Exhaust
230 Intake / 236 Exhaust duration
@ .050 - 110° lobe separation

Ignition Timing:

10-16° inital and total timing 32-34° at 3500 RPM

Also Includes:

Valve covers, oil pan and timing cover
Brass freeze plugs
Dyno test results shipped with engine

Warranty:30 month / 50,000 mile

Notes:

NEW BluePrint block manufactured
and machined in the USA!

Not for EGR

[Squirrely]

you should upgrade to a turbo400 trans. It won't explode like the 350 (or 700R4). Those are fairly big numbers for your current trans.