Gen VI 454 Into Small Block 79 K20 Questions

[HeavyMetalThunder_81]

I just picked up a Gen VI 454 from a '99 Chevy with 76,000 miles on it. I have just a few questions about installing it into my '79 K20 with a small block in it. I know something will have to be done with the engine mounts...just not sure what. And the biggest question...which flywheel should I use with my SM465? Should I use a Gen VI flywheel or a Mark IV flywheel? Also, which starter? Any and all help is appreciated. Thanks in advance.

[DirtyLarry]

You'll need a Gen V or VI flywheel. I have the part number but can't get to it today but it's the same part number as a truck with a L29 7.4L and NV4500. The starter motor is the same as any other Chev small block or big block (except LS engines). Just reuse your existing starter but you will need new bolts. I beleive the Gen VI has metric holes throughout. If you go to my picture link on Flickr below there is a set of pictures from when I ran a Gen VI 454 HO a few years ago. It was set up like a 96-00 L29.

[HeavyMetalThunder_81]

Originally Posted by DirtyLarry

You'll need a Gen V or VI flywheel. I have the part number but can't get to it today but it's the same part number as a truck with a L29 7.4L and NV4500. The starter motor is the same as any other Chev small block or big block (except LS engines). Just reuse your existing starter but you will need new bolts. I beleive the Gen VI has metric holes throughout. If you go to my picture link on Flickr below there is a set of pictures from when I ran a Gen VI 454 HO a few years ago. It was set up like a 96-00 L29.

I was hoping you would find this thread and post up. I thought I rememebered someone on here doing this swap but wasn't sure who. Thanks! So I would still use a clutch kit for my SM465, correct? And do you know what mods to engine mounts I would need to do?

[DirtyLarry]

Originally Posted by HeavyMetalThunder_81

I was hoping you would find this thread and post up. I thought I rememebered someone on here doing this swap but wasn't sure who. Thanks! So I would still use a clutch kit for my SM465, correct? And do you know what mods to engine mounts I would need to do?

Use whatever clutch you already have. I used a Centerforce for the model year of my truck but it really doesn't matter as all GM clutches are 10 spline but the pressure plates are a little different on the later engines with the one piece release bearing/slave cylinder.

No need to mod engine mounts. The sb mounts will bolt right on to the 454. 8.1Ls require a simple little grind of a boss at the mounting bosses but not the Gen V & VI.

[HeavyMetalThunder_81]

Wow, that is so simple it's crazy! I've been playing with AMC/Jeeps too long haha. Thanks for the help!

[DirtyLarry]

Originally Posted by HeavyMetalThunder_81

Wow, that is so simple it's crazy! I've been playing with AMC/Jeeps too long haha. Thanks for the help!

Finally got to a spot to actually fire up a computer. The manual trans flywheel part number for an L29 Vortec 7.4L is 14096987. I also use Centerforce clutch kit DF024909 (Centerforce Dual Friction 12" 73-95 7.4L).

Pictures of the 454HO swap from 2003 is here. And this SET of pictures is when it got a Marine MPFI fuel injected intake. I didn't like the way it ran so it got yanked and the 8.1L went in.

Funny, you mentioned AMC/Jeep as I just bought a ’77 Jeep J20 this past week for $400. I always like the old FSJ’s. Its got the typical 360/ 4 speed manual. Not sure of the transmission model yet but I think it is a T19. It needs a clutch and the trans release bearing collar that bolts to the front of the trans. Looks like release bearing seized and welded itself right to it. If the AMC Powertrain proves to be too bothersome to fix and source parts for it will be sporting GM Powertrain in no time. This truck will eventually get a slide-in wrecker unit that I have left over from another truck so I have a truck to use to drag home more crap found on Craigslist



Never mind the grill and horrendous bumper. I have a period correct winch bumper for it and the PO gave me a near mint grill along with headlight bezels.

[HeavyMetalThunder_81]

That '77 will have a T18 if its the 4 speed. T15 if it is a 3 speed. I've been playing in the FSJ game for the better part of 10 years almost.