Ignorant small block head and intake questions

[RichardWaller87]

After 243,*** miles, my stock 5.7 in my Suburban is starting to get more than a little worn out. I've been wanting to do some motor work. I recently got a parts truck with a good running tbi 5.7 that I'm planning on building and swapping in it in. I'm not planning on a super fancy build, just a cam and valve springs as well as a few parts to replace wore out stuff.
I should be able to just put my efi intake on the other motor shouldn't I? And as far as heads go, which would I be better off with, the Vortec heads on the motor that's currently in my rig or the heads off of the tbi motor?

 

[Awest623]

After 243,*** miles, my stock 5.7 in my Suburban is starting to get more than a little worn out. I've been wanting to do some motor work. I recently got a parts truck with a good running tbi 5.7 that I'm planning on building and swapping in it in. I'm not planning on a super fancy build, just a cam and valve springs as well as a few parts to replace wore out stuff.
I should be able to just put my efi intake on the other motor shouldn't I? And as far as heads go, which would I be better off with, the Vortec heads on the motor that's currently in my rig or the heads off of the tbi motor?

Vortec heads have a different intake pattern. You'll need to swap the vortec heads onto the engine to be able to mount the intake. Vortec heads are the best flowing OEM SBC heads ever made. You could always upgrade to E-Tek or AFR heads, but they're $$$.

Vortec heads only support up to about .48" of lift, I've heard of people running .5" but I wouldn't push it. If you're doing a cam I'd go ahead and mill down the valve guides and install LS style springs. They'll give you greater seat pressure and the ability to run higher lift.

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[Awest623]

After 243,*** miles, my stock 5.7 in my Suburban is starting to get more than a little worn out. I've been wanting to do some motor work. I recently got a parts truck with a good running tbi 5.7 that I'm planning on building and swapping in it in. I'm not planning on a super fancy build, just a cam and valve springs as well as a few parts to replace wore out stuff.
I should be able to just put my efi intake on the other motor shouldn't I? And as far as heads go, which would I be better off with, the Vortec heads on the motor that's currently in my rig or the heads off of the tbi motor?

You already mentioned valve springs, my bad

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[PlayingWithTBI]

Vortec heads are the best flowing OEM SBC heads ever made.

^^^What he said. There's another option with these heads, they flow a little better than the Vortec heads with 2.02/1.60" valves, AND have the TBI intake bolt pattern. Note: that price is for the pair, they're rated for up to .480" lift (I measured them @.484 and still had plenty of room before spring bind), you can install better springs so you can go higher. Keep in mind the TBI block takes a flat tappet cam unless you have the bosses for the spider, which you'll probably have to tap, to run a roller cam.

https://www.summitracing.com/parts/sum-162108/make/chevrolet

 

[RichardWaller87]

So with the Vortec heads and and intake on the tbi block I shouldn't have any issues as long as I go with a flat tappet cam that stays within 0.48 lift. Thank y'all, that helps a ton. Any recommendations for a cam? I'm after the aggressive, lopey idle sound.

 

[Schurkey]

So with the Vortec heads and and intake on the tbi block I shouldn't have any issues as long as I go with a flat tappet cam that stays within 0.48 lift. Thank y'all, that helps a ton.

Might want to look at getting pistons for a Caprice TBI instead of a Pickup TBI or Vortec 350. The light trucks used dish pistons, the car TBI had flat-tops. A bit of extra compression. The rings are different for the Caprice TBI compared to Vortec. Get the correct rings, too.

Be sure to mill the block; at least have it cut "square" to the crankshaft, but better yet would be to cut enough from the block for proper squish/quench. The piston shouldn't be more than .010 below deck if you're using a .028 head gasket. If using a .039--.040 gasket, zero deck would be better.

If it was me, I'd make sure to use an OEM-style roller cam and lifters rather than flat-tappet. This is even more important if you're moving toward stiffer valve springs. The block is likely set-up for roller cam provisions. As said, you might have to drill and tap three holes in the lifter valley. You can buy the roller-cam parts used, or take them off your Vortec engine. There's two designs for the thrust plates, you'll need whichever thrust plate fits your block.

You'll need the Vortec damper, timing cover, water pump and front accessories and accessory brackets. The TBI stuff is different. [EDIT]And the Crank Sensor Reluctor![/EDIT] TBI doesn't have a crank sensor, the rest of the parts need to be used as a "set" to make the belt alignment work.

Any recommendations for a cam? I'm after the aggressive, lopey idle sound.

It is BAT-**** CRAZY to buy a cam based on how it "sounds" instead of how it makes power. Buy a cam that RUNS GOOD instead of "sounds mean". You screw-up the camshaft, you'll be playing games with the computer tune trying to get back the power you threw away.

 

[RichardWaller87]

I realize buying a cam purely based off of sound is silly, however, considering what its going in any power gains will be great. Getting it to sound good and run right are my main priorities though, as with 37's I feel like it won't feel a whole lot different. I've some done motor work before, just never on a motor ran by a computer.

 

[Awest623]

I realize buying a cam purely based off of sound is silly, however, considering what its going in any power gains will be great. Getting it to sound good and run right are my main priorities though, as with 37's I feel like it won't feel a whole lot different. I've some done motor work before, just never on a motor ran by a computer.

I'll tell you now. Computers don't like huge cams. You can get a big lumpy cam to work. But it's a pain in the ass to tune idle. Depending on how big it is you might not be able to even run a MAF sensor. Might have to run it on speed density only. As a general rule MAF is more precise most of the time and would give you better gas mileage.

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[Awest623]

And also, big lumpy cams produce very little down low torque. Which is what you'll be needing with tires that big on a heavy truck.

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[Awest623]

And another caveat. Lol. The stock vortec intake manifold basically stops flowing at around 4000 rpm. Big cams don't make power till high rpms.

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