400 build from the bottom up, any advice?

[eg30.06]

hey guys new to the forum i have a 4x4 1995 silverado reg cab stepside 35s thats my toy. motors got 230K on her and still running strong but i think its time change her out. i bought a 400 off a buddy of mine for 200, had a spun rod bearing so i was going to just change that out and redo the top end but found alot more wrong with it. crank was walking a lil to it scored the main journals and the rod bearings really destroyed the crank. the block was already bored .30 and had a .03-4 ridge. being the siamese i didnt want to have to go another 10 0r 30 over. so i found another block on Craigslist with alot of performance work done to it and was already bored .30 honed and ready to go for 600. had oil screens, was a two bolt main but was modified into a four bolt main. i have double hump heads for it that need work and can get a pair of brand new vortec heads for real cheep. im looking to get anything over 350 HP just want some really great street performance so more torque and some more RPMs. any pointers or thoughts on the build? i am open to any suggestions.

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[eg30.06]

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some pictures of the rod bearings and components

 

[eg30.06]

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the new block. just wondering why did the thread and plug the oil valleys in between the lifters??? in my other block theres no plugs and they are not threaded either.

 

[clubber]

I am interested to see what comes of this. I too have a 400 block and I'm gonna be building it for my L31 replacement. I'm planning on 10 to 1 pistons and a high torque cam. Don't know on heads yet but a FIrst TPI intake.

 

[Chris]

You're looking at maybe 250hp if you keep the TBI system. If you ditch EFI, you're going to sort out how to make your transmission (if it's an auto) among other things function.


OR, you could rebuild what you have, throw on Vortec heads and a GOOD tune, spend the rest in gears and have something more responsive, reliable and fun to drive. Mechanical advantage is your friend with a heavy, lifted truck. If you've already swapped to a lower gear for oversize tires, you might as well go lower if you don't plan on spending hours on end at 70mph. Horsepower doesn't mean anything if it's lugging with a tall gear.


Also, * ubiquitous point about an LSx swap that would be about as much work as getting an ancient motor like that in and running properly, and it'd make more power and do it at 20mpg.

 

[eg30.06]

You're looking at maybe 250hp if you keep the TBI system. If you ditch EFI, you're going to sort out how to make your transmission (if it's an auto) among other things function.


OR, you could rebuild what you have, throw on Vortec heads and a GOOD tune, spend the rest in gears and have something more responsive, reliable and fun to drive. Mechanical advantage is your friend with a heavy, lifted truck. If you've already swapped to a lower gear for oversize tires, you might as well go lower if you don't plan on spending hours on end at 70mph. Horsepower doesn't mean anything if it's lugging with a tall gear.


Also, * ubiquitous point about an LSx swap that would be about as much work as getting an ancient motor like that in and running properly, and it'd make more power and do it at 20mpg.

I am doing away with the tbi fuel system and going carb. i already have a holley 650, just needs a rebuild. i am looking for about 10:1 compression ratio so ill either have to get flat top postons of shave down the heads. i have pretty much made my mind up and am going with vortec heads. i am gettinh the 202/160 valves put in along with getting them mechined and valves shaved to accept a larger cam. i think the way that vortec heads are factory can only take up to a .540 cam. along with getting screw in rocker studs. the only thing scaring me is the 450 for getting all the head work done.

 

[eg30.06]

Forgot to add, i have the factory 5spd in her now baut can get my hands on a nv4500 fairly easyly so i dont have to worry about stll converters.

 

[94_C/1500]

If you're building a 400, might as well either use Vortec heads or a nice set of aftermarket heads. If you use Vortec heads, you will need to drill steam holes and unshrouding the valves. I'd go with 2.02 and 1.6 valves and port the heads.

I haven't used them myself but I have met people that swear by Rhoads lifters. If I ever get another motor for my CJ8, I'm gonna give them a shot, hopefully a 385. But I need to stike oil if that build ever happens soon. If you use Rhoads lifters, you can use a monster cam and it'll still run pretty much like a small cam on the lower RPM. Just make sure you have the heads and intake to support that kind of cam or you're wasting your time if you go this route. Plus, if you enter competions where there is a vacuum limit (usually 15 inches) then using those lifters will allow the use of a big cam and still make the required amount of vacuum.

A decently built 400 shouldn't have a problem making 350 hp.

 

[eg30.06]

nobody ive heard has said anything bad about the vortec heads their plentiful cheep and have a great flow chart for factory heads. aluminum heads are just to dang expensive for me.

 

[eg30.06]

Does anyone know why the oil drains between the lifters would be threaded and plugged??? Sorry about the bad picture but you can kinda see the plugs I'm talking about in the above picture of the new block.