I'm getting ready to build an engine for my k5. It's lifted 9" on 38's on 1 ton axles with 3.73 gears and a th350 with a stock stall. I've hit a bit of analysis paralysis on how to move forward on the build and could use some thoughts. No, I'm not doing an LS swap.

Currently it's got a 4 bolt 350 bored 60 over in it with stock heads and pistons and a flat tappet RV cam in it. It works but meh. I've got a set of vortec heads I'm having cleaned up to throw on here to help for the time being.

The truck is just a toy. I drive it around town, I take my kid in it, I take it rock crawling, I drive it to work. But I'm a power junky and just finished my dad's 77 bronco with a nasty little 306 in it and can't have him beat me.

I've got a 350 block with stock crank sitting around. My initial thoughts on the build are I beam rods with arp bolts, balanced rotating assembly, forged flat top pistons (thinking around 9.5-10:1 compression), main studs and girdle, aluminum heads, cam, roller rockers, dual plane intake, Holley sniper EFI. I like rpm and like to over build. I haven't ruled out forced induction or nitrous (because how cool would that be) but I'd be surprised if I did either.

Here is where I'm hung up. Should I go ahead and have the vortec heads I'm putting on the original engine machined for higher lift and screw in rocker studs and pocket ported instead of aluminum heads? Am I wasting my time with the 350 rotating assembly and should I just jump to a 383? Is the girdle a waste of money? What about the I beam rods and bolts? I'm thinking something around 6000-6500rpm redline but it's gotta be smooth enough that my throttle isn't on off and the cam so radical that I can't control it while on a 30* incline.

Thought, opinions, comments? Tell me I'm an idiot or I'm way off base. I'm just stuck on how to proceed and need some ideas bounced around. No, I'm not doing an LS.

 

Fast Burn aluminum heads and 383

 

5.29s and leave it be


or LS swap it 😂😂

 

5.13 or so gears in the axles should be your first change. High stall converters offroad just build up a ton of heat and it will be even worse with 38's/3.73's. On road it will still be a lazy dog.

I run 4.88's in my blazer with 36" tires. It drove better both at take off and holding speed at highway speeds with the 36's and 4.88 than it did with the 31's and 3.73's. Solid axled s10 blazer with the stock v6.

 

You need lots of cubes and lots of low end torque

I say big inch SBC 400+ Ci or BBC

The vortec heads will be a great upgrade for an in-between build, but in the long run I wouldn't invest any more money in them.

 

Gears are on my list for sure. I'm leaning towards 4.88's because I'm planning on dropping tire sizes to maybe a 36". Whichever way I go I'll be ditching the goofy 20" wheels on there now.

 

38's and 3.73's seems a bit off. I would want a little more gear.

If you pull it, put a LS in it. Just my opinion.

 

+1 on gears

 

Gears forsure.
I run 5.38s with 35"s and also with my 33" slicks. I do have overdrive tho.
Some 4.88s would be a night and day difference over the 3.73s.
Years ago I build a 383ci stroker, with ported vortec heads, 2.02 1.60 valves and it was a torque monster. I yanked the front tires on the street all the time.

 

Ive been thinking about this thread since last night. I have a 22r crawler, 5.29s and 33s. She is slow as *****, and even with all that gear I am never above 4k (not really any power higher than that anyway)

My suggestion to you would be to leave a stock stall and optimize low end and mid range. I wouldnt get hung up on an RPM goal so much as a low to mid range grunt build. RPM= HP, you dont need a lot of HP, but you do need a lot of grunt