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Discussion Starter #1
So................ Many...........Damn............Choices.................


Previous Set Up:

91 heavy half-ton 3.73 gears, 4x4, lifted 4"
2.5 duel in duel out exhaust, Flowmaster 40's, x pipe
ZZ4 Crate motor L98 heads unported.
ZZ4 roller cam
Lift: .474'' Int. / .501'' Exh. 208° Int / 221° Exh. @ .050'' Lift
112° Lobe Centerline RPM Range: 3500-6500
ZZ4 Chev. Per. Intake-dual plane, spread bore
Holley 670 dp truck avenger/ edel. 750 man. choke




I am LOST....:rolleyes:.. The 1.94/1.50 L98 heads had good low, mid torque.

What is going to be a step up head that flows better (170ish) for street fun and keep that LOW/MID TQ because i rarely run it above 5500rpm.

$+durability+reliability+functional= what head for this big truck???


Thank you! :spank:
 

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Bottom end tq. is more of a function of camshaft then cylinder head so to speak. Less cam for better drive-ability and those heads should be good for that.

Big truck/big tires. These trucks really need 4.10's if running 285's/32 inch or bigger tires.
 

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The ZZx's are good all around engines... that ZZ2-ZZ6 cam is more for 1000 - 6000 RPMs range... so OK... for more low - mid RPMs torque, would prolly consider a long tube TPI intake setup... a longest runner tallest dual quad tunnel ram intake... or something like the 1950's-60-'s Chrysler long ram tubes setup...


https://www.hotrod.com/articles/hrdp-0902-small-block-chevy-bolt-ons

Or best of all, a 400" crankshaft/rods/pistons kit... I'm not talking parts from a stock SBC 400, but a stroker kit with about 3.85 - 4" stroke (I forget the exact numbers) that turns a 350 into a 400... I know Hot Rod has an article on doing that, but it is hard to find...

Also, could put a SBC 400 short block under your current heads, intake, cam, etc...
https://www.motortrendondemand.com/...th-one-bolt-on-engine-masters-ep-1/0_aq9h0374

Kits to convert your 350 into a 383 (with .030" overbore) are easy to find and start out at about $600... enginekits.com

GM has a crank that turns a stock bore 350 into a 383...
https://www.hotrod.com/articles/gm-ht383-crate-small-block-tune-up

TORQUE varies with cubic inches, intake manifold runner length... but HP is about the same for a particular heads/cam combo no matter how many cubes underneath them...

Hipsters suggestion of bigger rear gear is worth considering...

Stock iron Vortec heads might help, but more for mid RPMs on up...
 

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For a thousand bucks, I'd put a 383 kit in the bottom end, if the bores are good leave that alone and build it as a 377. Leave everything else alone, that will make a torque monster the half ton 4x4 needs under the hood. The L98 heads are pretty decent, L31's or aftermarket heads would to varying extents trade bottom end torque for top end horsepower, this is an OK trade if you gear into it and don't mind listening to a higher winding engine all the time. You have to remember that Chevy put sequential port injection on the L31 which covers a lot of the lower end torque drop, a carb or throttle body injection is not as good at that trick so in the end the L98's rather level the field a lot unless you do these additional things.

Bogie
 

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Discussion Starter #7
Im just doing a top end job to get torque and highway manners (mpgs).


Its a heavy truck and had the L98'S with a 4.00 bore. It was decent torque and decent mpgs on the highway and sounded good with a .474/.501 cam i have.


Im looking into the Super 23 heads that flow better than the L98'S AND VORTEC heads...... the 1.94/1.50 valves.

I have read allot on "bolt on dont do" threads.................

Real question is........... Do i buy them? AND if i do, Do i buy them bare and have my machinest assemble them or complete and have machinest check them over??????????????????/
 

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