Another aluminum head question.

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PlayingWithTBI

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It was my assumption that I'd have to match the cam to the springs (or vice versa) on whichever heads I do get.
To a certain extent, yes. you won't need excessive seat pressure or rate but, again with the stock TBI cam, it won't matter much. When you start getting into higher lift and duration, you want stronger springs. Flat tappet performance cams can be susceptible to higher wear due to too high spring pressure but, not in this case.

I'm also assuming that my advantages here, over stock heads, would be weight reduction and better air flow.
Yes, along with a proper tune (not just a mail order one) you'll see a larger gain in efficiency, power, and then, MPGs.
 

Schurkey

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Alright, finally a question directly regarding a GMT400. We all know my junk by now... 89 RCSB 4.3L MT, swapping to a 94 5.7L and keeping the MT.

SO! I'm making the swap to aluminum, NON Vortec heads. Anything has to be better than those junk smogger heads that came with the engine. I've been doing so much research that my head is starting to confuse one set of heads for another. UGH!

AFR seems to be a top choice for budget vs performance and reliability, but here's the catch: I'm sticking with a stock cam, which is hydraulic tappet. Not going roller cam at this time.

I have these heads in mind right now: https://www.summitracing.com/parts/AFR-1006

Any suggestions? I know some of us here have gone this route, so the input is appreciated.

These replies are all good reads, but NONE of them answer my question.
What question? The only one I know of from your first post is "Any suggestions?"
 

DeCaff2007

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What question? The only one I know of from your first post is "Any suggestions?"

Ok lol my bad.

Any specific heads I should be looking at? I was going to throw a link up to generic, bare, chinesium heads.... as a joke, but I decided against it.

Also, I've been reading this thread by @PlayingWithTBI: https://www.gmt400.com/threads/my-flat-tappet-cam-wiped-out-so-i-decided-to-go-roller.60167/

A few things here. First of all, those heads aren't even available from Summit anymore, although I think they seemed like a good fit, initially, for my application.

Second, the difference in spring height threw me off. Shims? What? My machinist mentioned shims, too. WHY? What is the purpose of shimming a valve spring if you have to match the springs to the cam?

Next, that thread is what helped my decision to stay with a stock cam. Also, according to Motor Trend, I don't need (and shouldn't use) a hot cam if my heads are garbage. Why bother?
 

Schurkey

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www.summitracing.com/parts/tfs-30310005/make/chevrolet


(The TFS-30310006 is the same thing but with bigger valve springs that you don't need.)

TFS-branded heads with TBI intake-manifold bolt pattern. Has center-bolt valve cover holes, so stock covers would work. Stock-size valves but that's not "really" a hold-up on a TBI engine. 2.02/1.60 on a TBI is more bragging-rights than actual performance. Extra-small combustion chamber to improve compression ratio. Hydraulic flat-tappet-compatible valve springs. Emissions-legal. (Has drilled passage for exhaust crossover, allows EGR but not excessive exhaust gas flow into intake manifold, preventing over-warming the manifold in summer.)

Made in USA although probably with imported parts--I don't know that, but I suspect it.

Downsides: Not actually in stock, estimated availability mid-June. Angled plugs may make header selection difficult. Kinda depends on HOW they're angled. An e-mail or call to TFS or perhaps Summit might clear things up.

For the record, I've got two pair of (older, different design) TFS heads with "angled" spark plugs; one pair on my 'Camino, the other on my '88 K1500. Plug access with Edelbrock shorty headers on the K1500 is WONDERFUL. Plug access with whatever brand of cheap-junk longtubes on the 'Camino is entirely adequate if not spectacular. So I'm probably biased in favor of TFS.
 
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Schurkey

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Shims? What? My machinist mentioned shims, too. WHY? What is the purpose of shimming a valve spring if you have to match the springs to the cam?
Springs need to have appropriate seat and over-the-nose pressure to suit the cam and lifters. But to get the proper seat pressure, the springs have to have the proper installed height. Shims are used to get the installed height correct.

Since the valve retainer height varies depending on how recessed the valve seat and valve faces have been machined (or worn), shims are used to compensate.
 

Vikingdude

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I think shurkey nailed it with that recommendation. The smaller intake runner is advantageous if the plan is to use the stock cam. I know its a little more money, but its a better head for the specific application.
 

DeCaff2007

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www.summitracing.com/parts/tfs-30310005/make/chevrolet


(The TFS-30310006 is the same thing but with bigger valve springs that you don't need.)

TFS-branded heads with TBI intake-manifold bolt pattern. Has center-bolt valve cover holes, so stock covers would work. Stock-size valves but that's not "really" a hold-up on a TBI engine. 2.02/1.60 on a TBI is more bragging-rights than actual performance. Extra-small combustion chamber to improve compression ratio. Hydraulic flat-tappet-compatible valve springs. Emissions-legal. (Has drilled passage for exhaust crossover, allows EGR but not excessive exhaust gas flow into intake manifold, preventing over-warming the manifold in summer.)

Made in USA although probably with imported parts--I don't know that, but I suspect it.

Downsides: Not actually in stock, estimated availability mid-June. Angled plugs may make header selection difficult. Kinda depends on HOW they're angled. An e-mail or call to TFS or perhaps Summit might clear things up.

For the record, I've got two pair of (older, different design) TFS heads with "angled" spark plugs; one pair on my 'Camino, the other on my '88 K1500. Plug access with Edelbrock shorty headers on the K1500 is WONDERFUL. Plug access with whatever brand of cheap-junk longtubes on the 'Camino is entirely adequate if not spectacular. So I'm probably biased in favor of TFS.
That's not bad at all. I wonder if that's the price for the SET, or for ONE head.
 

DeCaff2007

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I think shurkey nailed it with that recommendation. The smaller intake runner is advantageous if the plan is to use the stock cam. I know its a little more money, but its a better head for the specific application.
Agreed. It will probably take me until June to get everything else ready to bolt those on, so maybe the ship date isn't so much of a problem.
 

PlayingWithTBI

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It will probably take me until June to get everything else ready to bolt those on, so maybe the ship date isn't so much of a problem.
If you want them, order them now, that's what happened to the Summit Racing ones, they had an estimated ship date for a while, then all of a sudden, they changed it to "not available".
 
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