GM Tech Sticky

Robert1320 · Jun 7, 2007

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First, thanks to everyone in the GM section.
And all the GM guys! #ad
OK, guys if you have some good tech that SHOULD be in the GM Section.
Send me a PM with the info or a link to the info.
I am going to lock the post so it is not cluttered with BS and keep it as a Tech Only.

Begin!

Oh, if there is a link or topic that you more info about,
Start a new thread and we will discuss.

If all else fails .

Topic: THINKING ABOUT GOING BLOW-THRU........READ THIS BEFORE POSTING (Read 18681 times)
https://www.theturboforums.com/smf/index.php?topic=51153.0

Robert1320 · Oct 4, 2013

Where to find GM Casting Numbers

GM Casting Numbers
www.nastyz28.com/sbchevy/sblock.html

Robert1320 · Oct 4, 2013

GM small block info Gen I - II

Link From. #ad
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"How much power will my stock block small block chevy take"

While these are generally held conventions, your milage may vary. There are members making a lot more then 600hp off of a basic 2 bolt fully cast 350 short block.

Gen I 350 blocks
-basic 2 bolt 350-good to ~600hp
-basic (OEM style) 4 bolt mains 350 block good to ~800hp
-Splayed bolt billet caps ~1000hp

One piece rear main blocks are generally considered weaker then earlier castings, and reccomended power levels are ~600hp.

72 and earlier castings are generally considered to be the strongest, while the 350 blocks with the "010" as the last 3 digits of the casting number generally are considered to be an excellent candidate for a performance engine due to the cosnsistency of the casting.

Production 400 blocks are generally considered to be on "borrowed time" for anything but a very mild turbo setup, they didn't use a lot of metal in the blocks and they can be plagued by consistency issues and cracking in the main web. The 2 bolt blocks are also said to be stronger then the 4 bolt blocks.
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HEADS

There are 4 different OEM styles of head that will bolt on to a gen I small block chevy. These are pre 86, 87-95 heads, 96+ vortec heads and Gen II LT-1/LT-4 heads. LS1 heads will not work on a gen I/II motor.

Gen I heads-(pre-86)
Unless it's an ultra low buck setup avoid the castings that are 462624 and 333882. These heads are thin castings, and have heat issues as well. A turbo setup can excabate these issues, and cause these heads to be more crack prone as well. if you have a 400 SBC, don't forget to drill steam holes in your heads if they don't have them, otherwise you'll end up with heating issues.

Gen I heads-(87-95)

The biggest difference between these heads and pre-86 heads is the intake bolt pattern. The center 4 bolts are different, a lot of people mod the intake by slotting these bolt holes and using washers. All aluminum TPI (corvette) heads are pre-86 style, regardless of the year they were made. The TBI (L03, L05) heads are generally considered to be very poor performers, and while the intake won't cripple performance as much on a forced induction engine, TPI heads are generally considered better. These heads also use center bolt valve coves versus the "perimeter" valve covers.

Gen I heads (96-03 Vortec)

There are two different variants, most people think of the 350 version however if you're building a hot 305 motor they made a version that's very nice for 305s too. Avoid the 1996 castings, they are known for cracking. The intake on these has taller runners then 95 and earlier heads, as well as they do not share the same bolt pattern as either. You'll also need self aligning rockers or guide plates to use these heads. Like the 87-95 heads, these also use center bolt valve covers.

Gen II heads (LT-1, LT-4)

These heads put out pretty decent #s stock for flow, however they are unique to the LT-1/LT-4. The LT-4 has taller ports then the LT-1 heads, as well as using a different intake casting which is also not directly compatible with the Gen I motors (see above) These heads have reverse cooling ports in them, this makes them unuseable on a gen I motor without a lot of work, like plugging up the reverse cooling passages and milling the heads, it's been done but the effort is probably not worth it unless you get a set for cheap or free.

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Production cam info:
http://www.engineparts.com/motorhead/techstuff/stockcspecs/chevrolet.html
https://www.z28.com (scroll down)

Something to note is that the TBI 9C1 caprices used the stock TPI cam

(L31 Vortec) 96-03 similar to LT-1 B/D body engines
(I/E)
.414/.429
192/197

24502586 Hydraulic Roller (LT-4 Hot Cam)
.525 lift w/1.6 rockers
218/228 @.05
112 LSA

12551705 (LT-1 F/Y body cam)
.447/.459 w/1.5 rockers
205/[email protected]
117 LSA

12551142 (Prod LT-4 cam)
.476/.479 w/1.5 rockers
203/[email protected]
115 LSA

Please note you have to cut the pin shorter on the gen II cams to get them to work with a gen I motor since it's longer for the optispark. These will fit in a roller motor (87-2003 gen I) with no other modifications however.

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BlownShovel · Jun 11, 2007

Robert...I'll use this as my scratch pad... Organize the info where it fits in the thread....

Torque and other Specs
SBC
http://www.boxwrench.net/specs/chevy_sb.htm
BBC
http://www.boxwrench.net/specs/chevy_bb.htm

on the G.M. tech sticky

it should be noted in the torque settings post that it is common practice to
torque cylinder heads on BBC and SBC with 7/16 studs to 80lbs

I know some guys that torque the LS1 over 85

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Robert1320 · Oct 4, 2013

GM EFI Info

common GM fuel injector sizes
3800 Supercharged Series I (92-95)-28.5 lb/hr
3.8L Grand National (84-87)-28 lb/hr
3800 Series II/III Supercharged (96+)-36 lb/hr
5.0L TPI (LB9)-19 lb/hr
5.7L TPI (LB9)-22 lb/hr
5.7L LT1 24 lb/hr

some common GM ECUs that are native to forced induction applications
1227165
1227148
1227749
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Robert1320 · Jun 18, 2007

Rear end ID

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Robert1320 · Jul 18, 2007

Good Coolant pic

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Robert1320 · Aug 24, 2007

Firing Order Swap

Ok, here goes.
I personally like the swap firing order for the earlier Chevys. I also like it for the Mopars.

The person responsible for the LS Chevy firing order did this for longetivily and reasons of a smoother sounding and smoother running engine. This is not done for increasing horsepower, but maybe in certain combinations there can be a slight horsepower improvement. Steve Lowe of LSM worked closely with the section in Chevrolet responsible for crankshaft design, in developing the 4/7 - 2/3 swap to improve crankshaft harmonics. If any additional power is developed in doing this it was not part of the plans for design changes.

Way back in the mid 1980's Warren Johnson submitted to NHRA the idea of allowing a swap in firing order of the 4/7 swap. This was submitted for the purpose of slight horsepower improvements by better stablizing the cylinder temps in in the 5 and 7 cylinders getting away form the two rear cylinders on driver's side that are next to each other from firing consecutively which has been shown to give more cylinder heat to those cylinders under normal conditions. By swaping the 4 and 7 firing orders so those cylinders then were not firing consecutively, enabled those cylinder temps to be more stable which in Pro Stock 500 Cu In Engines was a slight hp improvement. By doing that 4-7 swap that made the two front cylinders on the passenger side to have the same issues but now it is different becuase those two cylinders are the first two to get fresh cooloant, unlike the 5 and 7 which got collant last in the cololant flow cycle. The negatives of the 2 and 4 firing consecutively were not any problem with cylinder temps. NHRA refused this and it was not until many years later with several teams all requesting this together that NHRA relented and allowed it. Now this is so common that every cam company offers the swap as an option for an additional fee. Even the shefl stock cams with the sawp cost more money for no better reason than it is a profit maker in many instances.

Current NHRA 500 Cu In Pro Stock Chevys are using this swap with also the addition of swapping the 2 and 3. The swaping in the Chevy of the 4/7-2/3 is called a C swap and in certain engine designs can show an improvement. There is also a Pro Stock firing swap for the Big Fords too. The Mopars in Pro Stock are doing the same swap as the Chevy.

In your particualr engine it may help slightly in hp but if so it will likely be a single digit improvement and will cost more money. I am not aware of any negatives in this but far too many guys ask for the swap firing order thinking it a magic bullet to major hp increases. That it is not. It can improve in the harmonic twisting forces your crankshaft sees. That is why it was done in the first place.

You can read on some webpages and in magazine write-ups that swapping the firing order to the 4/7 will give better fuel distribution becuase it keeps one cylinder from robbing the cylinder next to it. Bull!. Not possible. Any possible saw you can make to the firing order will still result in two cylinders next to each other firing consecutively. So you are taking whatever problems that 5 and 7 may have and moving that same problem to the 2 and 4. How can that improve fuel distributiuon problems. Or you are moving the problem to the 2 and 3. No matter what you do ar swap it will result in two cylinders side by side firing one after the other.

Most people selling the swap cams have no clue why the lobes were even swapped.

My two cents in opion is If money is not a problem, you may help your engine by doing the swap. If you improve your performance it will be a side benefit becuase of all of the rest of your combination just working well with the swap. If your entire package is not matched to work better with it, the swap will benefit you zero performance gains.

Ed Wilson

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Robert1320 · Sep 17, 2007

LS SERIES CYLINDER HEADS

LS SERIES CYLINDER HEADS
Part Description Material Port Port Valve Chamber Int Exh Plug Heat Rocker Notes Page
Number Size Type Angle CC's Vlv Vlv Type Riser Stud Number

12480005 C5R 1st design Aluminum 210 Rec C5R 11 deg 38 2.18 1.63 Angled No Shaft As-cast, no seats/guides N/S

12480090 C5R 2nd design Aluminum 210 Rec C5R 11 deg 30 2.18 1.63 Angled No Shaft As-cast, no seats/guides 230

12564824 Stock LS6 Aluminum 210 Cath 15 deg 64.5 2.00 1.55 Angled No Bolt Hollow/sodium filled valves 228

88958622 CNC LS6 Aluminum 250 Cath 15 deg 61.9 2.00 1.55 Angled No Bolt 11.2 compression 228

88958665 CNC LS6 Aluminum 250 Cath 15 deg 65 2.00 1.55 Angled No Bolt 10.5 compression 228

12564825 Bare LS2 & LS6 Aluminum 210 Cath 15 deg 64.5 2.00 1.55 Angled No Bolt Bare LS2/LS6 228

12576063 Stock LS2 Aluminum 210 Cath 15 deg 64.5 2.00 1.55 Angled No Bolt Solid stem valves 229

88958765 CNC LS2 Aluminum 250 Cath 15 deg 64.5 2.00 1.55 Angled No Bolt Solid stem valves 229

12582714 Bare L92 Aluminum 260 Rec L92 15 deg 70 2.16 1.59 Angled No Bolt Bare L92 229

12582713 L92 Aluminum 260 Rec L92 15 deg 70 2.16 1.59 Angled No Bolt Solid stem valves 229

12578450 Bare LS7 Aluminum 270 Rec LS7 12 deg 70 2.20 1.61 Angled No Bolt Bare LS7 230

12578449 Stock LS7 Aluminum 270 Rec LS7 12 deg 70 2.20 1.61 Angled No Bolt Titanium/sodium filled valves 230

25534428 As-cast LS7 Aluminum '” Rec LS7 12 deg 66 2.20 1.61 Angled No Bolt As-cast, bare head 230

Robert1320 · Oct 2, 2007

GM Trans ID.

thats easy to id ... look at the pan here is a good pic to tell ya what it is
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1 Aluminum Powerglide 14 bolts
2 TH200 Metric 11 bolts
3 TH350 13 bolts
4 TH400 13 bolts
5 TH200-4R 16 bolts
6 TH700-R4, 4L60, 4L60E 16 bolts
7 4L80E 17 bolts

some more useful info

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Drac0nic · Oct 4, 2013

Just as a note, there are 3 distinct SBC timing cover/balancer positions. There's one at ~2 degrees to the left of the crank key, there's one ~20 degrees to the left of the crank key and there's one ~40 degrees to the left of the crank key. These will wind up at at a 2:30, 1:30 and 12:00 position respectively. If you mix and match your timing cover and balancers, it's best to get a piston stop and verify.

TTF/Ken · Jun 5, 2014

Small Block Chevy - How to Check for True Top Dead Center And Check for a Spun Damper Hub

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GM Tech Sticky

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