Double Hump thoughts:

[Old60Driver]

Found a set of rebuilt double hump heads (casting # 3782461) that I can pick up for 400 bones. I've been toying the idea of getting a better flowing set of heads to go with a RV torque cam for my 83 K20, and thought this might fit the bill.

What say y'all?

 

[Bextreme04]

Found a set of rebuilt double hump heads (casting # 3782461) that I can pick up for 400 bones. I've been toying the idea of getting a better flowing set of heads to go with a RV torque cam for my 83 K20, and thought this might fit the bill.

What say y'all?

I wouldn't bother... that's way too much money for ancient heads that probably still need $600 worth of work to make them flow as well as stock vortecs.

Also, depending on what you have now, you would be dropping from a 75cc chamber to a 64cc chamber with the 461's and also they likely have completely worn out valve guides and non-hardened exhaust seats. If you want cheap stock replacement heads that will help your performance, maybe just get new heads from summit: https://www.summitracing.com/parts/sum-152123?rrec=true

or new Vortecs : https://www.summitracing.com/parts/...2RqD2xArM6_O5Q6218Q3BnzE1uGRFfh4aAiPoEALw_wcB

 

[Old60Driver]

After I posted this, I was thinking the same thing. Just too much trouble.

I've had my eye on the 152123s for a while now. I'm thinking that with those heads, and an 1103 cam, it should wake this 68,000 mile motor up at bit.

How does that sound?

 

[Bextreme04]

After I posted this, I was thinking the same thing. Just too much trouble.

I've had my eye on the 152123s for a while now. I'm thinking that with those heads, and an 1103 cam, it should wake this 68,000 mile motor up at bit.

How does that sound?

I decked my block, went with flat top pistons, and ran a refreshed set of 820's with a K1102 cam. Its basically a stock idle, but feels better all the way around. It's snappy off idle and pulls solid through the whole range. I bet your setup with an 1103 would be a bit rowdier, but still have a good solid idle and good vacuum. It would definitely be a big improvement over stock.

 

[Raider L]

I agree, don't bother with the double hump heads. There's no way whoever you bought them from could document what they've been through. It would be a shame to do all the work they would need just to have them crack the first time you got into it. There are great heads after market that would hold up forever and do more than you could ever get out of those old heads. Keep them though, you never know what they'll be worth in a couple of decades.
I do have Z28 heads on my engine only because it's a whole Z28 engine with better 300 hp heads we found that had been milled .020". So we machined them out to 2.02" x 1.60", stainless valves, polished the combustion chamber, and gasket matched it. Then I got a set of Lunadi roller rockers, Melling performance springs. Oh yeah, we put in the hardened exhaust seats and did the three angle valve job on the seat and the valves. No fancy retainers or high locks, just what came with the springs. Was it worth it over just getting a pair of Edlebrock heads or Vortecs? I don't know. I just wanted a real Z28 engine in my truck, it already had a real Z28 short block in it from the factory and we all stood there looking at each other wondering how the heck a Z28 engine got in a light duty pickup, and that's what I got.

 

[C10MixMaster]

I guess I my thought were on something else. . However with all the aftermarket heads available now days rebuilding old ones are a waste of time and money

 

[Grumpy]

I agree with everyone on getting new heads. Things can get pretty expensive in a hurry when rebuilding old, old heads. Remember, you are only one crack away from throwing out the entire project.
Besides, the new heads will have the proper accessory mounting holes.
Leave those humpers for someone restoring a project.

 

[Old60Driver]

I agree with everyone on getting new heads. Things can get pretty expensive in a hurry when rebuilding old, old heads. Remember, you are only one crack away from throwing out the entire project.
Besides, the new heads will have the proper accessory mounting holes.
Leave those humpers for someone restoring a project.

The accessory holes (or lack thereof) is what really sold me on new heads. As well as having to potentially work them over to match my needs.

Thanks!

 

[Green79Scottsdale]

I will echo what everybody else said, and add this...

Locally I have a guy that sells Vortec's ready to go for $450. Just saying...

 

[Bextreme04]

I will echo what everybody else said, and add this...

Locally I have a guy that sells Vortec's ready to go for $450. Just saying...

Beware, if he is just taking old factory vortec heads and remanufacturing them, they are well known to have a problem with cracking. The summit ones are a remake of the chevy performance vortec heads that had a bit more meat in the right areas and didn't tend to have the same cracking issues. For the extra $150-200 I'd be buying new and save the future hassle.

For that price I'd also be worried about what he ISN'T doing to them also... he must be either getting the cores for dirt cheap or he isn't doing the whole 9 yards. Maybe no valve guide reaming or reusing some stuff.

 

[Old60Driver]

Beware, if he is just taking old factory vortec heads and remanufacturing them, they are well known to have a problem with cracking. The summit ones are a remake of the chevy performance vortec heads that had a bit more meat in the right areas and didn't tend to have the same cracking issues. For the extra $150-200 I'd be buying new and save the future hassle.

For that price I'd also be worried about what he ISN'T doing to them also... he must be either getting the cores for dirt cheap or he isn't doing the whole 9 yards. Maybe no valve guide reaming or reusing some stuff.

You bring up a good point. I've been tempted to go with vortecs, but have always shied away due to the cracking issue. If the summit brand vortecs have been re-engineered with a bit more meat, as you say, is the cracking still an issue that I'd need to be worried about?

 

[Green79Scottsdale]

Beware, if he is just taking old factory vortec heads and remanufacturing them, they are well known to have a problem with cracking. The summit ones are a remake of the chevy performance vortec heads that had a bit more meat in the right areas and didn't tend to have the same cracking issues. For the extra $150-200 I'd be buying new and save the future hassle.

For that price I'd also be worried about what he ISN'T doing to them also... he must be either getting the cores for dirt cheap or he isn't doing the whole 9 yards. Maybe no valve guide reaming or reusing some stuff.

That price was cleaned, magnafluxed for cracks, new guides, springs, retainers, and cleanup of the valve seats when necessary.

 

[SquareRoot]

I will echo what everybody else said, and add this...

Locally I have a guy that sells Vortec's ready to go for $450. Just saying...

@Rusty Nail

 

[Octane]

That price was cleaned, magnafluxed for cracks, new guides, springs, retainers, and cleanup of the valve seats when necessary.

Aluminum heads can only be vacuum tested or maybe a dye test,not magnafluxed for cracks according to the head shop in Atlanta where the head off my bros toyota were repaired.

 

[Green79Scottsdale]

Aluminum heads can only be vacuum tested or maybe a dye test,not magnafluxed for cracks according to the head shop in Atlanta where the head off my bros toyota were repaired.

You are correct.
The heads I am referring to are factory iron heads.