Need Help L29 Build Questions

[1952Chevy]

So 90% sure I will be rebuilding my L29. I have a 99 K2500 Burb(410 rear end), and will be using it to hunt/camp/overland/tow etc. While rebuilding the motor I figured I would do some upgrade since I'm in it already anyway.

Don't want to spend too much, and not looking for major HP/TQ gains. Just hoping to get some overall better performance, with better low end torque. If possible better MPG(not really important though).

For the bottom end, I don't plan on doing too much. Once I get the block to the machine shop they'll let me know what needs done. I'm assuming .010 or .030 over. Really only doing what is necessary.

For the top end I am looking to do a mild Cam, valve springs etc. The problem is I am super new to this. I have worked on cars my whole life, but never really did any engine building work. So I don't fully understand cams etc. I know how they work and have been doing research on different durations and lift and am starting to understand all that.

What would a good cam be for my application? What else would be required to make it run correctly?

I was looking at doing the Bosch type injectors, long tube headers, and true dual exhaust as well. Like I said just not sure how to put it all together, and a little overwhelmed with the information that's out there.

 

[Schurkey]

1. You have "Net Lash" rocker studs. They're not adjustable. Either you buy a cam with OEM base circle, or you upgrade the rocker studs and nuts to the older, adjustable style. Problem is, GM didn't drill and thread the rocker stud bosses in the head to 7/16-14 like in the old days. You'd need special "conversion" studs, or you have to have the heads drilled 'n' tapped to the larger size. When it was me, I just bought the ARP conversion studs.

2. You'll have valve rotators under the valve springs. Aftermarket springs won't like the rotators. You'll need two sets (16) rotator-eliminator shims. BEWARE of the shims not seating fully on the intake guides--the radius of some intake guides at the spring pocket is too large, has to be ground-down by hand. I had two guides on each head that needed to be touched-up.

3. Cut the block decks so that they're square to the crankshaft, and so the piston has proper quench/squish when using a typical-thickness head gasket. The amount that has to be cut from the block depends on the gasket you select. I'd be looking for 0.035--0.040 quench distance--and that's the thickness of typical gaskets, so the block needs to be cut so the piston tops (not the dome, if used) is level with the deck.

4. A large piston dome will hit the "widow's peak" in the combustion chamber of the L29 heads. May have to relieve that "widow's peak". I used small-dome pistons so there's wasn't any problem. Those pistons had valve reliefs intended for stock-size (2.08) valves. If you use 2.19" valves, beware piston-to-valve clearance. (I don't know if 2.19 valves will work in the L29 heads.)

5. The L29 heads have a ski-jump in the intake port. Very much like the crappy TBI small-block "swirl port" heads. They're biased for low-rpm power and fuel economy. There's no power above 5000 rpm. Maybe someone can port them so they make power. My engine was pretty lame. I got rid of the L29 heads on the replacement engine.

 

[Frank Enstein]

True duals is not the best setup. A properly done single will outrun duals all day every day.

Begin Flame Show in 3,,,2,,,1

 

[yevgenievich]

...

5. The L29 heads have a ski-jump in the intake port. Very much like the crappy TBI small-block "swirl port" heads. They're biased for low-rpm power and fuel economy. There's no power above 5000 rpm. Maybe someone can port them so they make power. My engine was pretty lame. I got rid of the L29 heads on the replacement engine.

Is there a picture of the ski jump thing in the intake? I have l29 style heads with adjustable valve train that have standard intake port, and intake port on my 97 l29 appeared to be the same.
Been looking for pictures before, but most I found were broken photobucket pictures

 

[Schurkey]

My other photos seem to be on a near-dead computer. I can't find 'em on this computer.

https://www.chevelles.com/media/l-29-heart-shaped-chamber.51992/

https://www.chevelles.com/media/chevybigblockl-29conversion012.54925/

 

[yevgenievich]

My other photos seem to be on a near-dead computer. I can't find 'em on this computer.

https://www.chevelles.com/media/l-29-heart-shaped-chamber.51992/

https://www.chevelles.com/media/chevybigblockl-29conversion012.54925/

Thanks.
The ski ramp reference is to the rotating ramp thing right in front of the valve? I was thinking of it different, like an actual small restriction of the intake port that would promote better mid and low end power. Will try to take a better look at the spare l29 style heads I have.

 

[Schurkey]

Blocking off one side of the port--from port wall to valve guide boss--IS a restriction.

 

[Carlaisle]

True duals is not the best setup. A properly done single will outrun duals all day every day.

Begin Flame Show in 3,,,2,,,1

I don't know if this is true of all engines, but it is definitely true on this particular engine. You want a 3.5" single exhaust. With the long tube headers, that exhaust will make a huge difference in power and slight difference in fuel economy. The long tube headers are a headache, but worth the effort. Be sure to only use mandrel bends in the exhaust.

 

[LC2NLS6]

Cam and springs and exhaust is probably best bang for the buck, with a tune. I really like my 215/215 comp roller magnum cam in my L19. My machinist removed the rotators and custom cut some polylocks down so they fit under the stock valve covers, with new adjustable full roller rockers, hardened pushrods too.

There's also a kit to convert stock non-adj rockers to adjustable too. https://www.summitracing.com/parts/CCA-4514-KIT

 

[smokymtn65]

GM performance is the only offer for 3/8in stud guide plates for the big push rods as far I know. GM # 12562369