97 454 L29 Vortec into a 80 K25

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.

Bextreme04

Full Access Member
Joined
May 13, 2019
Posts
4,439
Reaction score
5,581
Location
Oregon
First Name
Eric
Truck Year
1980
Truck Model
K25
Engine Size
350-4bbl
I’m just keeping it black like it was from the factory. I’ll do the headers, intake, and accessories aluminum color.
 

Bextreme04

Full Access Member
Joined
May 13, 2019
Posts
4,439
Reaction score
5,581
Location
Oregon
First Name
Eric
Truck Year
1980
Truck Model
K25
Engine Size
350-4bbl
Got the new lifters and retainers in
You must be registered for see images attach

You must be registered for see images attach


Then I bolted the spider retainer on and set the head gasket and driver side cylinder head on.
You must be registered for see images attach


Then I realized I had decided to use new head bolts and had thrown away the old ones so that I wouldn’t be tempted to reuse them. So I’ll go get a new set of mahle bolts tomorrow and get the heads installed. Then I need to get the holes plugged on the upper intake and prep the block and intake parts for paint.

You must be registered for see images attach
 

Bextreme04

Full Access Member
Joined
May 13, 2019
Posts
4,439
Reaction score
5,581
Location
Oregon
First Name
Eric
Truck Year
1980
Truck Model
K25
Engine Size
350-4bbl
Tried to go get new head bolts today. I was planning on getting the Mahle ones as they are the only alternative to felpro that can be had easily locally. Turns out they are direct order from the manufacturer only and I would have to pay shipping and wouldn’t get them until next week. Ain’t nobody got time for that. So I got the felpro set instead. They had them in stock and they look identical to the factory ones.
You must be registered for see images attach
You must be registered for see images attach


it’s nice they come with the thread sealant already(all head bolts go through to the water jackets and MUST have thread sealant) but I didn’t trust it completely and used some PTFE thread sealant over the top of what was already there just to make sure. Then I snugged them down with my trusty electric drill using a half inch socket to save some time and then torqued in three steps using this sequence and specs. Final torque is spec’d to 85lb-Ft for the Gen VI heads, so I just did the final step at 85 instead of 80.
You must be registered for see images attach


So that’s one side some and then on to the other side!
You must be registered for see images attach
You must be registered for see images attach
 

68post

very, VERY, limited access member
Joined
Feb 20, 2014
Posts
281
Reaction score
97
Location
Indianapolis
First Name
Tim
Truck Year
1984
Truck Model
84 K30 SRW Silverado, 85 C20 C6P
Engine Size
454, TBD
What did Delta grind the cam specs to ?
 

Bextreme04

Full Access Member
Joined
May 13, 2019
Posts
4,439
Reaction score
5,581
Location
Oregon
First Name
Eric
Truck Year
1980
Truck Model
K25
Engine Size
350-4bbl
What did Delta grind the cam specs to ?
Post #8 on page 1 has a pic of the cam sheet. Its a pretty mild tow/RV/mileage cam since I'm still going to be using the factory MPFI. The lift tops out at .510, which is perfect for the L29 heads that max out flow at around .500. Another nice thing is that they set it up 3.5 deg advanced, which is much nicer than the ~6 deg retarded of the stock cam grind.

The stock motor, at 288,000 miles, leaking oil and coolant everywhere and overheating, had sooooo much more power than my current 350 that I'm REALLY excited to get this thing done and installed in the truck. I'm really trying hard to hold it together and take my time to do it right and make it look nice at the same time.

My excitement is telling me to just slap it together and send it.:emotions122:
 

68post

very, VERY, limited access member
Joined
Feb 20, 2014
Posts
281
Reaction score
97
Location
Indianapolis
First Name
Tim
Truck Year
1984
Truck Model
84 K30 SRW Silverado, 85 C20 C6P
Engine Size
454, TBD
Post #8 on page 1 has a pic of the cam sheet. Its a pretty mild tow/RV/mileage cam since I'm still going to be using the factory MPFI. The lift tops out at .510, which is perfect for the L29 heads that max out flow at around .500. Another nice thing is that they set it up 3.5 deg advanced, which is much nicer than the ~6 deg retarded of the stock cam grind.

The stock motor, at 288,000 miles, leaking oil and coolant everywhere and overheating, had sooooo much more power than my current 350 that I'm REALLY excited to get this thing done and installed in the truck. I'm really trying hard to hold it together and take my time to do it right and make it look nice at the same time.

My excitement is telling me to just slap it together and send it.:emotions122:


Thanks, I did find post #8 but could enlarge it to see the durations or lobe seperation. I'm sure the advance will be a great boost off-idle TQ.
I do have an L29 core sitting for several yrs now but have decided to use an older block to have a mech fuel pump, and with vortec heads to build an 8.0L clone with a little warmer cam.( 496 or 506ci )
I am fighting with the notion to use the #781 heads that core came with and domed pistons, but I'd be better off and likely money ahead,( I think ?), to use L29 heads and flat pistons for 87 octane, and giving away some HP.
Buuuut, I may not get to drive it enough to worry about fuel costs also !!!??

I'll stay tuned, good luck, and smooth sailing !
 

Bextreme04

Full Access Member
Joined
May 13, 2019
Posts
4,439
Reaction score
5,581
Location
Oregon
First Name
Eric
Truck Year
1980
Truck Model
K25
Engine Size
350-4bbl
Thanks, I did find post #8 but could enlarge it to see the durations or lobe seperation. I'm sure the advance will be a great boost off-idle TQ.
I do have an L29 core sitting for several yrs now but have decided to use an older block to have a mech fuel pump, and with vortec heads to build an 8.0L clone with a little warmer cam.( 496 or 506ci )
I am fighting with the notion to use the #781 heads that core came with and domed pistons, but I'd be better off and likely money ahead,( I think ?), to use L29 heads and flat pistons for 87 octane, and giving away some HP.
Buuuut, I may not get to drive it enough to worry about fuel costs also !!!??

I'll stay tuned, good luck, and smooth sailing !

I think maybe it couldn’t be made bigger because I uploaded it as a thumbnail instead of a picture. Here’s the full photo.
You must be registered for see images attach


The combo of the flat top pistons and the L29 heads gives great daily driver CR and is pretty efficient. I’ve seen people in stock or slightly modified GMT-400 L29’s claim to get 12-15mpg, which is pretty awesome for a 454 making 3-400hp and 500lb-ft of torque.

One thing to look out for with the L29 heads is that there is no heat riser crossover, so it doesn’t do well with a carbureted application. Also the Gen V and Gen VI BBC has a parallel coolant flow that is different from previous generations and will need some interesting head gasket things depending on which block is combined with which heads.
 

Bextreme04

Full Access Member
Joined
May 13, 2019
Posts
4,439
Reaction score
5,581
Location
Oregon
First Name
Eric
Truck Year
1980
Truck Model
K25
Engine Size
350-4bbl
Well, didn’t get any work done on the motor tonight. Saw a Facebook marketplace ad pop up in @Catbox ’s neck of the woods for a 60 Gal craftsman air compressor... for $20!!! So needless to say I went up and got it.
You must be registered for see images attach


The oil free pump threw a rod and it’s old enough that you can’t get parts for it. Thankfully the motor is a 6hp 240v 1ph and is still in perfect working order. My neighbor just so happened to have his compressor lose the motor a few weeks ago and he bought a new one. He’s gonna bring it o we tomorrow and I’ll see if I can his pump working with my motor and have a working 60 gal for $20 and a few hours of my time!
 

Catbox

Full Access Member
Joined
Jul 12, 2018
Posts
4,452
Reaction score
16,682
Location
Just Outside of Portland Oregon
First Name
Peter
Truck Year
1979
Truck Model
C20 Silverado Camper Special
Engine Size
461
Market Place can get you to do funny things.
I went to McMinnville last week for a set of headers that may or may not work on the truck.
But the deal was just to good to pass up.

Nice score on the tank!
 

Bextreme04

Full Access Member
Joined
May 13, 2019
Posts
4,439
Reaction score
5,581
Location
Oregon
First Name
Eric
Truck Year
1980
Truck Model
K25
Engine Size
350-4bbl
Alright, got the shop somewhat sorted and got some time again to work on the engine.

I wanted to check the pushrod length because it seemed the ones my machine shop ordered were much shorter than the stock ones.

After fiddling with it for a while I realized that the measured length was pretty darn close to the ones the shop had ordered. The stock ones were a strange length that seemed almost based on the metric length, but the new ones were almost exactly .100 shorter. Which then clicked in my head and I realized that the heads had .05 taken off and the deck had also been milled the same amount. So I put the whole valve train together with those pushrods and they seem to be perfect.
You must be registered for see images attach
You must be registered for see images attach
You must be registered for see images attach
You must be registered for see images attach

The Gen VI BBC has this cool clip-in heat shield tray that keeps the hot oil from spraying up onto the intake.
You must be registered for see images attach
 

Bextreme04

Full Access Member
Joined
May 13, 2019
Posts
4,439
Reaction score
5,581
Location
Oregon
First Name
Eric
Truck Year
1980
Truck Model
K25
Engine Size
350-4bbl
Then I punched out the old seal on the timing cover and put a timing tape on the new harmonic balancer and clear coated it to keep it from flying off.

You must be registered for see images attach
You must be registered for see images attach

I still need to remove the cam gear and locktite the cam retaining plate bolts, since I forgot to do that when I assembled it the first time. Then I need to tack weld the oil pickup tube and then clean and paint everything.
 

Bextreme04

Full Access Member
Joined
May 13, 2019
Posts
4,439
Reaction score
5,581
Location
Oregon
First Name
Eric
Truck Year
1980
Truck Model
K25
Engine Size
350-4bbl
Everything has been on hold while my power has been out for the last 12 days. Power just got hooked up today, so hopefully I can get some stuff painted tonight and move forward with the build. Picked up a non-rust filled radiator from a 1998 C3500 with the 7.4 and an electric fan setup from a 2011 2500HD with HD cooling for $100 from pick a part. I should be able to set everything up and start it on the engine stand to make sure I didn’t screw anything up too bad and work through electrical issues before it’s all slapped in the truck.

You must be registered for see images attach
 

Bextreme04

Full Access Member
Joined
May 13, 2019
Posts
4,439
Reaction score
5,581
Location
Oregon
First Name
Eric
Truck Year
1980
Truck Model
K25
Engine Size
350-4bbl
Annnnnnnd connecting rod carnage....
You must be registered for see images attach


looks like the old engine just wasn’t going to wait for me to be ready

The engine is pretty much ready once I paint and assemble the accessories. I have all the parts to get the wiring harness finished and routed where it needs to go before firing it up and running it on a stand.

Transmission still needs to come apart and get inspected before I order parts for the rebuild. And I need to order the rebuild kit for the transfer case. I might just pull that now since the truck isn’t going anywhere anyways. Get the transfer out so I can machine the index ring on the adapter, clean and rebuild the transfer, paint it, and get the electronic vss sensor in it. I need to get the transmission parts ordered soon as they apparently can take a while to ship from the company I want to get them from.
 

Latest posts

Forum statistics

Threads
44,167
Posts
950,720
Members
36,282
Latest member
Doug Hampton
Top