How much HP will a th350 handle? New motor!

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Bextreme04

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Here’s the original 400

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That plastic fuel filter sitting right over the top of those headers is giving me the heebie jeebies man.... I'd recommend you change that out for a metal one or move it to a different spot with the line tied over the top of the intake manifold. If that cheap filter or one of those hose clamps let go, you're going to have an instantaneous and spirited fire in that engine bay that will be hard to put out before it totals the truck.
 

1979 K10

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That plastic fuel filter sitting right over the top of those headers is giving me the heebie jeebies man.... I'd recommend you change that out for a metal one or move it to a different spot with the line tied over the top of the intake manifold. If that cheap filter or one of those hose clamps let go, you're going to have an instantaneous and spirited fire in that engine bay that will be hard to put out before it totals the truck.
Good point. I’ll relocate to near middle of intake and possibly change to metal filter. I like being able to see through the plastic filter for fuel flow and debris.
 
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@1979 K10
Glad you kept the AC. Good choice on the new motor. That thing makes 450 lbs ft from 2800ish to 5600 rpm. It's gonna be a blast with those gears. I dig the air cleaner element too. Keep us posted and let us know if or when the trans gives up. Your trans was built at one point so maybe it has a chance to hold up.
 

1979 K10

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@1979 K10
Glad you kept the AC. Good choice on the new motor. That thing makes 450 lbs ft from 2800ish to 5600 rpm. It's gonna be a blast with those gears. I dig the air cleaner element too. Keep us posted and let us know if or when the trans gives up. Your trans was built at one point so maybe it has a chance to hold up.
Thanks!!! I couldn’t build my current 400 to those specs for that price and It’s a new block, no steam holes, etc. thought about LS swap but that’s a lot of work to get everything working, gauges, mounting points, etc. I’d rather keep it small block 400 powered.

ETA shipment from summit is 8/16 so may be awhile.
 

Raider L

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You know I've known a lot of guys who swear by 400's to race with, they wouldn't have it any other way. I've asked them about those dang "steam holes" in the block. I asked them, why didn't
GM just make an engine like a 350 but a bigger block to 400 cubes. That way they could have eliminated the steam hioles. That's where 400's crack. Now everybody knows about swapping out 400 cranks and rods into a 350, and visa versa for different engine configurations. But I never under stood those dang steam holes. What, they didn't want water in there? Why didn't they just let water in there?
 

Raider L

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@79 K10,

You were talking about that troublesome trans cross member. I solved the same problem with this:

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the center section with the trans mount is adjustable for TH350's , and TH400's.

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thick footing that is lined up with factory holes.

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1979 K10

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My truck is 4WD and the crossmember supports the transfer case. I believe it’s as easy as moving the stock crossmember back 3” and drilling new holes in frame. Issue is you have to shorten rear driveshaft and lengthen front driveshaft. I’ve hear of some people moving motor 2-3” forward. But worried that may affect weight balance since these trucks are already front end heavy and light in the rear.
 

82sbshortbed

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Built they'll handle 500hp.
 

1979 K10

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Have had the Blueprint 400 installed for over a year. Haven't put but 1k miles on it as it stays parked for the most part during the winter and I have other vehicles.

It runs very strong and the ol TH350 is holding up so far so good. I replaced the stock torque converter with this TCI 240900. It doesn't fully engage until 2400 rpm. About 1000 rpm up from stock. I've idled around offroad and can still crawl around at 1500rpm but when your on the throttle it lets the small block rev to 2200-ish, then really takes off.

I'm about to add these Vibrant 1141 Ultraquiet resonators to tone down the exhaust a little. Here's a comparison video. I will be installing them before the mufflers but just slipped them at the end of the exhaust to test the sound difference.
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1979 K10

Junior Member
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Flagstaff, Arizona
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Terrell
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1979
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K10
Engine Size
400
In cab startup with Blueprint 400, longtube headers, true dual exhaust with Dynomax super turbo mufflers.
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