My brother and I are dropping a 305 into his S-10 next year to replace his wheezing, dying 4.3 V6. I was planning on jsut rebuilding a 305 I had laying around from a 78 Malibu, with a little more compression and a little more cam but suddenly he got a killer-diller deal on a set of BRAND NEW Aluminum TPI Vette heads!

I know the chamgers are the right size (58cc) which will work well with the higher 9.7:1 compression we are going top run BUT....

Will the larger 1.94 intake valve hit the bore at .500 lift?

Will it perform noticably better than just slapping the stock cast iron 305 heads back on (they've got the small 1.74" intake valves and 1.50 exhaust)?

Is it generally worth doing for a mild performance application?

If we put them on we'll never take them off again and I'd hate to "waste" a good set of cylinder heads on a mild truck motor when they might be put to better use on a REAL performance motor elsewhere.

Anyone have personal experience with this kind of setup?

 

I put a set of aluminum vette heads on my old 305 TPI. It worked like a champ. I was consistantly running in the low 14's with the stock short block and a mild Lunati cam with about .485 lift. I don't think you will have to worry about those valves hitting the smaller bore even at .500 lift.

 

v8....in a s-10....whats to ask of performance?? its going to scream any way you go about it!! but, it should run even better with those heads on there and no, it wont have piston to valve clearnce problem if the pistons are flat tops. even with the 1.94/1,50 valves. it'll be fine with that set-up. happy burning!!

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89 firebird formula

356 10.5:1compression
comp cams xe262 cam
performer rpm intake
#1405 edlebrock 600
sportsman 2 heads 64cc 2.02/1.60 valves 200cc intake runner
msd 6al
h.e.i. proform 50,000 volt vac. advance ditributor
700r-4 with 3.08 first gear and 3.23 posi 7 5/8 rear end.
b trans shift kit(will kill shifts...suck dong!!)
shorty heddman hedders with custom 3" pipe y-pipe back(no damn cat!) with 40 series flowmaster!


future mods: 406 roller REALLY REALLY REALLY RADICAL!!!!!

 

Here's my setup with no piston-to-valve clearance problems.

305
Corvette Aluminum Heads (#113)
Crane 2032 Cam with 1.6 rockers
482/496 valve lift
Stock compression forged pistons.
0.051" head gasket for a CR of 8.912 to 1

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Willie

Supercharged 1987 305 IROC-Z, Daily-Driver, Emissions-Legal.
Paxton (6-psig): 12.57 @ 111 mph.
Paxton (6-psig) & 50-hp nitrous: 12.04 @ 114 mph.
ATI D1SC (10-psig): ?

http://willie.camaro-firebird.org/

1987 "20th Anniversary Commemorative Edition" Z28 Convertible -- Super Chevy Show Class Winner, 1998.

 

Alright, it's unanimous. Aluminum heads it is!

Yes, I'm using flattops (replacing the deep-dish pizza stockers) at a stock .025 deck height and a typical FelPro .038 head gasket for a CR of ~9.6, give or take. I'd like to tighten up the deck height some but we'll see about this.

The cam will have only about .450" lift so it sounds like I'm on safe ground. Thanks for the help!

 

Damon,

Repeat after me - You don't want those old 'Vette heads. (I don't want those old 'Vette heads...)

You want to send them to Vader instead. (I want to send them to Vader...)

Vader can use them on HIS 305 to make lots of power, and Force. (Vader can use them...Hey wait a minute!)

It's an old Jedi mind trick - at least it USED to work.

The valves will not interfere with the pistons if you have the stock valve reliefs and flat-tops. However, the valves may get close enough to the bores to cause some shrouding at the peak lifts, but will still allow more flow at the intermediate steps to provide plenty of mixture in the little engine's chambers. Just to make sure, check the valve/bore clearance when setting up the heads. Test springs are great for this.

If you want to minimize the shrouding effect, you can chamfer the front faces of the intake valves only to allow a smoother transition around the valve margins. (This is a circle track thing that can provide antohter 4-6 HP in a 358 CI engine, and should help flow in the small bores as well.)



STANDARD GRIND THREE-ANGLE GRIND RADIUSED FACE/MARGINS
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Later,
Vader
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"I'm'a do Things My Way - It's My way or the Highway."
Adobe Acrobat Reader

[This message has been edited by Vader (edited April 02, 2001).]

 

Vader, the mind trick almost worked- the heads ARE on their way to you! I'll expect that when I get them back from you in 2 weeks they will have the valves modified as pictured in #2, above.

Thanks! I appreciate the help!



Valves might get replaced with a set of Manley Race Flo stainless valves that are fully modified already- I have them laying around and might use them for this application. But then again, this IS a TRUCK motor, after all. I think my brother is going overboard just with the heads, let alone an expensive set of valves!