i was wondering if i should port my 305 heads and put them on my 350 or use the 350 heads i have on it? the engine is a 79 with low compression. its has 4.11 heads, edelbrock carb, headers and all those goodies but its still lacking something. and i dont have the cash to go buy 1200 heads so im looking for a better solution. would i gain more h/p and torque by porting the 4.11 heads or the 305 heads? and how much of a gain will i see? is it worth it? and what do most shops charge to port heads? just a ball park figure? thanks

 

i dont see 411 heads on mortec, but im guessing there around 76cc, but thats a guess, just because you say you have low compression.

I am in about the same postion

If your 305 heads are casting # 081 or 416 i would go with the 305 heads then.

I am not sure of the total gain, but i am using ported 081 heads, and i am hoping for high 13's.

I am not sure what a shop would charge to port heads, but it wont be cheap. Paying a pro for 20 hours worth of labor is never cheap. I am porting my own...spent about 8 hours on them, and almost done with the first head.

good luck

 

300-600 for a basic street/strip porting job

 

wow, now i know why everyone does it on their own

 

Yep, 100% Labor...and we know how that goes.

 

You can wake up your 305 heads with home porting
and larger 1.94x 1.60" valves.

Search my past posts. Loads of info there.

You can do better yourself than your money will buy U at a shop.

Too labour intensive.

Are they actually "416" heads? ( last three numbers under the valve covers)

Your true compression ratio may still be too low
even with small chamber 305 heads (58cc)

Factory dished piston ed low compression motors can have a large piston to deck clearance spec.
You may want to measure and calculate your true compression ratio and tweek the heads a bit (milling) to get it where ya want it.

Remember that after you enlarge the 305 heads' combustion chamber a bit for the larger valves they will be right about 60/62cc's
so you can/ may shave 'em a bit.

 

No such thing a "4.11" heads..... that's a rear end gear ratio, maybe other things too, but not any SBC heads I know of.....

If they're the stock 79 Z28 heads, they're probably 882s, and they suck. Get rid of them. Almost anything else is better. About the only worse heads would be late 70s 267/305 2-barrel heads. They're thin and weak in several places, don't take well to porting because they're already so thin there, and otherwise just generaly suck (no matter what size valves somebody sticks into them).

305 4-barrel or TPI heads are a better platform to start from. That would include the ones off of LG4s and L69s (416 casting), or the later-model 081 casting.

 

they are 411's, they are out of a 79 3/4 ton chevy truck. im gunna do some searching and find out how to port my own heads, does anybody know if they make a kit or anything? and will milling the heads raise the compression? thanks

 

You going to put in the larger valves and all the work that goes along with that yourself there guy? Buying the valves, having a shop cut the seats, etc cost money. Not bank breaking money for a shop to do it including the parts, but to spend money on 305 heads you're going to port yourself for your first time and expect performance? I'd skip it...

Why don't you just buy some Vortec heads ($420ish new, plenty of used ones around) and a new intake and call it done... Their 64cc chambers will bump your compression up a bit too...

 

Well, I bought my 416's New with 2.02 valves...pocket ported and deshrouded..... #110 springs, machined for and including screw-in studs and guideplates.....64cc Cost.....$500. Now if I want more lift than .510 I will have to have them cut out for the larger springs. I thought about Vortecs...But I didnt want to be stuck with the more expensive intake..not to mention centerbolt valve covers..another $100 And then the cost of upgrading the heads themselves, for larger springs...and maybe the bigger cam to handle more rpm...
My friend has the vortecs on his 87 Iroc 350/T-5...the car runs good..high 13's But it craps out at 5500rpm and the valves float like crazy...I could rev higher wit my 462's . Sure he could fix this but now we are talking more machine work......
I'm sure SittingBull will have something to say about the comment above.....

 

Standard Abrasives Deluxe Porting Kit, Summit p/n SAI-260001, $39.95. Comes with a poster-size guide to porting with good text instructions and photos. They just happened to use 416 castings for their illustrations. I did my heads using this kit/guidelines, 1st timer.

You'll also need a 1/4" collet die grinder. Either electric (Dremels don't cut it), or air with a "real" 5 HP air compressor or larger (not this "peak HP" rating stuff).

Milling the heads would raise compression. Makes more sense to put in pistons with less of a dish, and reducing the deck height of the block.

 

Nope! You've become a good disciple of F-Bird'88--he will be proud

 

LOL! SittingBull , you crack me up! Here is a link to the heads I just got what ya think?

http://community.webshots.com/album/64079524WgJvED

 

Looks like they could use some work..hey guys

Is this the Sears Model?
http://www.sears.com/sr/product/summ...id=00902744000

 

Need variable speed.

The heads need port/chamber polishing, sharp-edge removal, port-gasket-matching at least. Probably guide smoothing.

 

whats guide smoothing?? i am porting my 081's right now, how do i smooth the guides out?

 

i think that is a good idea. has anybody bought a set of already ported 305 heads or maybe a good set of used aftermarket heads? im really not wanting to spend over 450-500 bucks to do this. and next winter ill probably have enough saved up to put some better pistons in it and or a better cam and intake manifold.

 

I dont think you will get the Vortecs installed for 500.00

 

i just looked through a pace1 performace catalog adn they have a set of cast iron vortec special performance machined heads with 64cc combustion, 1.94 intake, 1.50 exhaust valve and i think they are complete. they are 386.00. how hard is it to install a set of heads and what else will i need besides head gaskets and valve cover gaskets? what about the fast burn heads? anybody have them? they are 587.50 but if they are worth it i might go for those. they have 62cc chamber, 2.00 intake, 1.55 exhaust valve

 

from the pace 1 website...

Please call 1-888-748-4655 for item details. Americas favorite high-performance cast iron small block cylinder head offers big power and bigger value. The Vortec cylinder heads fast burn combustion chamber and high velocity ports combine to produce big horsepower out of the box.The Vortec head cam be mildly ported for additional performance and can be milled up to .040"for increased compression ratio. The Vortec head uses 1.94" intake valves and 1.50" exhaust valves to compliment the high velocity port design.The Vortec head out flows the Bow tie head out of the box and is a 20 to 40 horsepower bolt on increase over earlier cast iron small block heads. The Vortec requires a Vortec style intake manifold due to its improved manifold mounting flange and gasket design and raised intake ports. It is not recommended that the heads be modified to accept early design intake manifolds. Manifolds available are P/N 12366573, 12496820, 1249621, 12496822. Vortec heads fit all small block engines produced 1955 to present, excluding LT1/LT4 reverse coolant flow engines and current LS1 style engines. Heads come completly assembled with valves, springs, retainers, and 3/8" rocker studs. Requires the use of selfaligning rocker arms. The valves seats in these heads can be machined to 2.02" intake and 1.60" exhaust. The rocker arm studs can be pinned or drilled and tapped 3/8".

http://www.paceparts.com/search.asp?7=12558060+&1=Go

you will need the intake with the heads.

 

Those heads appear to be in very good shape. You have the right idea. Take your time working them over and you'll have a set that will make you happy for many moons

 

I plan on starting the porting when I get back from my vacation in sunny Tucson first week of March....Ill be talking to ya..

 

Here are directions to build your own electric die grinder speed controller

AC electric die grinder speed controller.

You can build a speed controller out of parts from a
hardware store. You'll need

1. square wall electrical box (fits two wall plugs or a wall plug and a switch.
2.A double wall plug receptical
3. a ceiling fan speed controller or light dimmer
(get the one without a radio interference filter)
4. some marret connectors
5. A length of AC lamp cord
6. A AC plug.
7. A wall plate. combo 2 plug and round hole.

Wire the box up using the lamp cord and marrets so the dimmer controls one plug outlet only according to the diagram.
That way you can use the other for a work light.
Just turn the dimmer to control the speed of the die grinder.

Note: The dimmers with the radio interference filter will fail after a short time
so get the one without the filter.

 

That is a Terrific Idea! So would the craftsman in the link above be ok?