L31 with LT1 bottom end

Any recommendations on valve covers that will clear 1.6 roller rockers and polylocks?

UPDATE: I got this running and had an issue with my tall TBI style valve covers I got from KMJ on ebay. They look factory but the holes are all wrong for the Vortec PCV system. Also they fit and clear great until you bolt them down. With a little gasket squish they hit the trunions and I had to trim the bracing... found this out after initial start-up and it sounded horrible. Had a rocker arm come off because of the contact and I thought it was all over. Fixed that and distributor timing then it ran a TON better. Seems to run really strong even with the stock tune but now I am questioning my Vehicle purchase. Alternator is dead, starter works intermittently, distributor cap tabs are stripped out, and has terrible driveshaft vibration (i even washed all the mud out of the wheels).

Shorty headers with dual glasspacks and a cam sound good enough I want to fix all the issues and give this thing a good rip. Does Blackbear do good tuning with aftermarket cams? or would I be better off on my own with EFI Live (I already have it just don't want to license the PCM if I am going to 0411 it later)

Crazydavez28 said:

UPDATE: I got this running and had an issue with my tall TBI style valve covers I got from KMJ on ebay. They look factory but the holes are all wrong for the Vortec PCV system. Also they fit and clear great until you bolt them down. With a little gasket squish they hit the trunions and I had to trim the bracing... found this out after initial start-up and it sounded horrible. Had a rocker arm come off because of the contact and I thought it was all over. Fixed that and distributor timing then it ran a TON better. Seems to run really strong even with the stock tune but now I am questioning my Vehicle purchase. Alternator is dead, starter works intermittently, distributor cap tabs are stripped out, and has terrible driveshaft vibration (i even washed all the mud out of the wheels).

Shorty headers with dual glasspacks and a cam sound good enough I want to fix all the issues and give this thing a good rip. Does Blackbear do good tuning with aftermarket cams? or would I be better off on my own with EFI Live (I already have it just don't want to license the PCM if I am going to 0411 it later)

Click to expand...

Tune it yourself. Not much to it that I couldn't walk you through.

Crazydavez28 said:

Any recommendations on valve covers that will clear 1.6 roller rockers and polylocks?

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I have the Comp Pro Magnum roller rockers with shorter Crower poly locks and stock valve covers. I had to trim the supports in the valve cover due to rocker width, but managed. Left support is trimmed, right is stock.

L31MaxExpress said:

Tune it yourself. Not much to it that I couldn't walk you through.

Click to expand...

Is it a waste to tune the black box? Not sure how long im gonna keep this tahoe. I did the 0411 on my 454 but I plan on keeping that in the fleet.

Crazydavez28 said:

Is it a waste to tune the black box? Not sure how long im gonna keep this tahoe. I did the 0411 on my 454 but I plan on keeping that in the fleet.

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There's a good bit to be gained by tuning a black box. The 411 is just that much better. BB is not a waste to tune by any means.

Supercharged111 said:

I have the Comp Pro Magnum roller rockers with shorter Crower poly locks and stock valve covers. I had to trim the supports in the valve cover due to rocker width, but managed. Left support is trimmed, right is stock.

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I need to look into some shorter pushrods and the short polylocks. I would like to see the stock valve covers back on this motor.

Ive got this thing running OK. Seems to not want to idle well until revved on startup. Shiftpoints seem too soon. Short list of maintenance is intake gaskets, transfer case output seal, and fuel filter.

I question everything on the 'Roadfar' distributor when the cam sensor plug wont snap in place because the tab is too wide. I have 100 miles on the dizzy and want to inspect the gear. While I have it apart I am going to check the distributor stem size on this Chinese unit to see if it is all at once causing my oil pressure to drop. I had 60psi cold pulling into my shop and 40 psi cold after changing distributor and setting the CMP. Idles at 20psi on the gauge when warm (it was higher before) I changed oil filter and no debris.


I'm starting to look at different intake manifolds but the juice doesn't seem worth the squeeze if I'm keeping the black box. I did notice the Taylor Cable 11011 plenum spacer increases volume and HP. Thinking it might actually be worthwhile since I have a marine cam and brand new MPFI.


I do have a leftover LT1 intake to modify for future use if I want to go that route. Has anyone ever modified this to fit the Vortec bolt pattern?

Crazydavez28 said:

I need to look into some shorter pushrods

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Why? Are the pushrods you have so long that you don't get proper sweep at the valve tip?

"I have 100 miles on the dizzy and want to inspect the gear."

There are tons of melonized gears at Pull-A-Part on Vortec distributors. It's a five-minute swap while you have the distributor out. I put one on my TBI distributor since I'm running a roller cam.

Edit: I agree with Schurkey. Don't shorten your pushrods to gain rocker clearance. You'll change where your rocker tips push on your valvestems, and you could cause accelerated wear, or even a valve tip to chip.

The marine cam is drop in and go as far as valvetrain geometry goes. The variable here is the non-stock rockers.