[Silver79]

I've been asking lots of questions on the forum lately as I've been planning to build my first big block. I've ported and flowed the L29 style cast heads and now disassembled the short block which is off to get cleaned and cam bearings on Monday. I think I'll document here. Scat forged crank 4.25, scat 6.385 rods, silvolite pistons. Heads are bowl blended ported and I'm working on the valve job currently. Cam and springs coming from CStraub and I'm learning about big block valvetrain daily. More to come.

 

[69-CHVL]

Will those pistons clear the L29 chambers?

 

[Silver79]

Yeah, those are a slight dish rather than a dome. They ran like that in its former iteration as a generator. I'm just cleaning it all up. Checking clearances and doing a cam swap.

 

[Malibu ss 64]

Nice build! 👍🏻
Are you going to run stamped steel rocker arms? If check slot to rocker stud clearance.

 

[shovelrick]

Have you found that you'll be able to use stock length PR's or will you need to measure for custom length? I'm guessing stock length is fine with stamped rockers

 

[Janih]

How did the heads flow?

 

[Silver79]

Nice build! 👍🏻
Are you going to run stamped steel rocker arms? If check slot to rocker stud clearance.

I would like to run roller rockers, my current studs may be too short for them though. Been pouring over the forum and necessary stud length seems to vary by brand etc...need to get the cam and springs in my hands I guess.

 

[Silver79]

Have you found that you'll be able to use stock length PR's or will you need to measure for custom length? I'm guessing stock length is fine with stamped rockers

I have some comp brand length checking rods but it's all going to depend on once the actual cam and springs are in. Much like the rockers.

 

[Silver79]

Janih,
Long story short, about 4% better than stock.
Here is the link to the thread with the flow numbers.

Bowl cleanup on "L29's" with flow numbers

 

[69-CHVL]

Yeah, those are a slight dish rather than a dome. They ran like that in its former iteration as a generator. I'm just cleaning it all up. Checking clearances and doing a cam swap.

generator huh - guess why the thing is so clean inside?

Couple tips with Gen VI Vortecs. Guides would only handle .500 or less, so they would need to be cut down. Looks like those heads had some mods already as I see an adjustable valve train. Get 3/8 guideplates for larger pushrods. I only had about .050 piston/valve clearance using a ZZ502 cam, not sure what will happen with those pistons. Keep the factory spider tray arrangement despite who tells you otherwise. If those are GM lifters I'd reuse those.

 

[Janih]

Janih,
Long story short, about 4% better than stock.
Here is the link to the thread with the flow numbers.

Bowl cleanup on "L29's" with flow numbers

Ohh sorry! Now I remember. Straub made me custom roller cam for gm roller lifters, that is going to my 509cid peanut port engine. I try to dyno it In next few months.

 

[Silver79]

So, here is my current question for you more experienced guys. My current studs are about 1-1/2" long above the top of the nut. About how much stud will I likely need if I were to switch to a roller rocker?
I think this may be dictated by the brand of rocker. Probably, spring and pushrod choice too? The way I understand it.

 

[Malibu ss 64]

View attachment 702967 So, here is my current question for you more experienced guys. My current studs are about 1-1/2" long above the top of the nut. About how much stud will I likely need if I were to switch to a roller rocker?
I think this may be dictated by the brand of rocker. Probably, spring and pushrod choice too? The way I understand it.

Those studs wont work with roller rockers.
With your heads you are limited to the conversion studs from arp/comp/crane. Or have them drill and tapped for 7/16 studs.
your l29 heads have 3/8” threads vs 7/16 for earlier heads.

 

[Malibu ss 64]

Here are the conversion studs

ARP 135-7102 ARP High Performance Series Rocker Arm Studs | Summit Racing

Free Shipping - ARP High Performance Series Rocker Arm Studs with qualifying orders of $99. Shop Rocker Arm Studs at Summit Racing.

www.summitracing.com

3/8”-16 base thread ok to around 400lbs open so of under that and long enough they will be ok. If more pressure or not long enough dril and tap for 7/16(very importent it gets straight)

 

[Silver79]

Thank you for the info. Well, interesting. The cam card calls for open pressure of 400. Springs are spec'd to that. Looks like I would be at capacity. Decisions....

 

[Janih]

Thank you for the info. Well, interesting. The cam card calls for open pressure of 400. Springs are spec'd to that. Looks like I would be at capacity. Decisions....

Straub custom cam?

 

[Silver79]

Straub cam. I think he called it semi-custom. It's one that's listed on the site.

 

[shovelrick]

I have a set of ARP studs that were too short for my build and I had flat cut the exh. studs threads that go into the head (Course) a little shorter since they bottom out in my Brodix heads, I'll make a very good deal on them if they'll work for you, shoot me a PM if interested and I can send pics, measurements

 

[Silver79]

I have a stroker clearanced big block at the machine shop for a pressure check, bake and blast, hone and cam bearings. 16 year old me would give 39 year old me endless high fives.

 

[pbcbob]

must be a serious generator to use a 250hp? engine, natural gas powered? must use a lot of them to have their name cast on the block