HELP! LS1 to SM465 Headers

[AMERICANBADASS]

I recently bought a pair of the Speed Engineering 1-7/8” Long Tube, Part #25-1026. They’re for LS based heads, with more of a round inlet. I’m pretty sure I need the Part# 25-1028, for LT based heads.
The description on their website says “not compatible with 4WD”. I’ve seen multiple people online with them, and they seem to fit.
Does anyone have any first had experience with these? I have a 2004 LS1, from a Silverado 1500 that’s going into a 1980 K20, with a manual SM465. Does anybody know if the headers will clear the clutch linkage?

 

[yevgenievich]

What is a 2004 lt1?

 

[AMERICANBADASS]

The motor is out of a 2004 Chevrolet Silverado 1500, so I believe that it would be an LT1. The LT1 is the truck version of the LS1. I could be mistaken though.
The truck I’m converting is a 1980 K20 with an SM465. I’m concerned that the driver side header is going to hit the clutch linkage between the frame and bell housing, right at the firewall.

 

[AMERICANBADASS]

I stand corrected. The LT1’s are truck model years 2014+

 

[Nicholson72]

Another guy in these forms is running speed Engineer headers his clears, I have schoenfeld headers on my truck, I have the hydraulic slave cylinder and they clear it with a lot of room

 

[AMERICANBADASS]

Thanks for the response Nicholson. I got the motor set close to in place, and it looks like they might clear. It’s definitely going to be close.
Good point with the hydraulic slave cylinder. Did you use a conversion kit, or farm fab it?

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[Nicholson72]

Looks good, I bought a 87 3/4ton and pulled all the stuff and swap it into my truck and put my auto back in the 87 and sold it and made my money back, so it’s all factory looking

 

[yevgenievich]

My vote is for hydraulic clutch set up. But standard truck headers tend to hang low and might work ok with mechanical clutch

 

[AMERICANBADASS]

Thank you for the reply, yev. I got the motor, transmission, and headers installed into their final resting place last night. They fit great! Below the clutch linkage, above the cross member and everything clears. Even the 02’s! I don’t know why anybody would buy anything else, these things are bad ass! I’m tempted to buy the rest of the exhaust kit

 

[Nicholson72]

Thank you for the reply, yev. I got the motor, transmission, and headers installed into their final resting place last night. They fit great! Below the clutch linkage, above the cross member and everything clears. Even the 02’s! I don’t know why anybody would buy anything else, these things are bad ass! I’m tempted to buy the rest of the exhaust kit

I wanted speed engineer headers but they said they won’t sale to California people even tho the company is a few hours away, but I kinda wish I went with a mid length header the long tubes are a little long and put them in a weird area to build the rest of the exhaust off of