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Discussion Starter #1
So today I went around and found a machine shop that would check the bore measurements and bore it to 30 over on my 305 engine. I also asked if they port and polish heads also. He said that they always have work coming in and stay busy and that they don't do it because it is to time consuming for them to be able to and he also told me that there is no one in the Savannah, Ga. area for performance upgrades. I looked around on the internet and the phone book and he is right, there is no one in this area that will do it. I've seen them being done on the internet and it doesn't look to be that difficult. Is it possible to port and polish at home or are there to many special tools and machinery needed?
 

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port and polish heads

What is your goal with your engine. Racer, economy, daily driver? As for P & P heads, why not invest in a good set of free flowing after market heads?
 

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Well.....if there was a low-buck answer to your question, you mighta figured I would come up with it.


Do it yourself!!!!!!!!

http://www.cylinderheadsupply.com/2587dx.html


a tip......don't polish the intake ports/passageways. you want the rough surface (as cast) to create enough turbulence to keep the fuel droplets in suspension. if they are polished, tests show that you need to keep the velocity of the intake charge WAYYY UP in order to keep it mixed. However, polishing the exhaust side is like greasing it so that the exhaust gasses shoot right thru there. matching the ports to the gaskets is always good, just don't go any farther inside the ports than about an inch.

:poke: :nanawrench:
 

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why not just put a 350 crate engine in it? you'll get more power and a warrenty for about the same money.
 

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X2 what Keyser said,,, for a 305 match port the intake/exhaust,, get a book on porting,, you can do damage and decrease power if done wrong,, a minor P/P is what you need,, I bought a kit from Summit Racing,, I am going to do my 355 and I just got another project,, it is a curse!! I bought a 96 1500 surburban 2wd truck,, it has a 5.7 vortec motor with 277,000 miles + but has always had Amsoil oil in it,, I plan on pulling the motor and do a overhaul,, but read up and do it,, I will post up pics when i do mine,, Matty man
 

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X3 on what Keyser said....and porting a 305 will not show much performance difference in the seat of the pants indication. And un-shrouding the valves usually drops the compression ratio a bit, due to slight enlargement of the chamber.
On the other hand, it's good experience for you, if you do it yourself. But like said, get some info on porting before you wade into it. It's a dirty job too, with cast iron dust & chips getting on everything etc. And have fun !:smileyb:
 

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Just put a 350 in it you will have more power better MPG youll have everything that a 305 will never have even if you do the work to it.
 

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want to practice on something "lifelike" before trying to p/p a head? Port/polish a stock exhaust manifold. very comparable skills involved, polishing the inside of the manifolds WILL improve the exhaust flow, and if you mess it up, it's only an exhaust manifold (cheap and easy to find a replacement for) and not a head.

:poke:
 

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Discussion Starter #9
Thanks for the tips. Does anyone recommend a certain manual for doing this or just browse around and find one?
 

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My advice...Don't do it...
Buy a 350, or a new set of heads like others have said.

The first pair of runners are fun...the next seven is a trip through hell...
Grinding on cast iron will fill your lungs with the best of breathers.

You will need all 8 to match...CC the intake runners before and after....over & over...
For street RPM you will need the roughness on the "LONG" side of the intake runner to keep the fuel mixed. Unshrouding the valve and pocket will be the biggest improvement. Port matching the intake and head are next on the list...

This really is a science, and with the new CNC heads, almost a lost art. To do a propper job would take at least 20 hours...For $1,500-$2,000 in labor you are better off with new....Thats why no one does it anymore! Full Race iron heads done by hand would take more like 60 hours...You can do the math on that one $$$

If you really want to drop $1,200 into a set of stock heads to keep matching numbers on a car...or are drag racing, Look into "Extrude Honing" ... Killer, really works magic for high RPM motors!

Again...I did porting & CC'ing on heads 30 years ago for two reasons 1) That's all we had 2) Young and Stupid! With all the new hardware out there...Buy New, or leave it alone....Once you pick up that grinder You will wish that you never started...
 

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Hi Jeremy, and a belated welcome to region seven. I have read this thread and your other "rebuild" thread and thought you had decided to pass on the 305 build. When I read the first one, I remembered a build Chevy High Performance did on a 305. Last night I looked through back issues and found the article. If you are interested in ordering them, part one is June 2004 and part two is september 2004. I'll give you a brief (maybe not so brief) synopsis. They knew a guy with a very nice, 305 powered, third gen Camaro and offered to give it more power as a magazine feature. They wanted to stroke it but he wanted to keep it a 305. The 305 was built as a economy, emissions friendly engine and it's cylinder heads restrict it from making good power. Their plan (I wish I had their money) was to put a set of Vortec heads on it because of their excellent capabilities. Getting the Vortec's to work on the small bore a 305 was the task of Superior Automotive. They mentioned that their shop truck powered by a 100000 mile 305, with an old 300hp Chevy cam, a 600 cfm Holley, "and a little bowl work" (probably much more than that) on the heads, they managed to get 230 rear wheel HP. The Vortec's have a larger chamber so they needed to be milled to get the compression back. They did some port work on them as well. Here are some flow numbers they listed. There is a chart but I will give you just the numbers at .5 valve lift to compare. Stock 305- 150int,138.5exh, Vortec- 215.1int,152exh, ported Vortec- 252int,181.1exh. This with other machining to get them to fit and to get everything bolted back on that came off, came to $2400 and that does not include the cost of the heads. A dual pattern Crane cam was used, lift with 1.6 rockers is .510int .520exh, duration @.05- 210*int 214*exh. This was a TBI engine and was to remain that way. The original throttle body could not keep up with the new breathing capabilities so that was changed to a larger unit and the ECM re-calibrated. Here are the dyno numbers, keep in mind these are rear wheel. This car has a 700r4 and they estimate a 22 percent loss if you want to convert to crank numbers. Base 305 144.9 hp @ 3400, 229.2 lb-ft @ 3000. With Vortec's 229.8 hp @ 4700, 295.4 lb-ft @ 3800. Vortec+new tbi 256.87 hp @ 5000, 295.31 lb-ft @ 4000. All this after they put a ton of money into it. What it did for the Camaro "Not that we approve of unsanctioned acceleration contests on public roads, but we will say that a 97' SS Camaro and more than one Mustang Cobra have already been abused by our creation (we don't count anything with a wing or a coffee can)." Keep in mind this is in a third gen Camaro, a fourth gen El Camino is a good bit heavier.
 

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Discussion Starter #12
For some reason I just really want to go with the 305? Maybe stupidity or just stubbornnness. I do know a 350 or 383 stroker would be the best route for power. I have listened to the advice of everyone on here and decided to not port and polish and from your post CANTED I have decided that big power is out of the question. My next idea right now is to just build back to stock and open up the air flow(new intake and exhaust manifolds, cold air intake and pipes)to save up money for a 350 crate. I saw one in jegs that HKDUP(sorry if spelled wrong) was saying he bought for $1,500 pushing 250hp in a thread. I think I am trying to do to much on my first build. I am not trying to build a racer or drag car just a weekend driver that has power. I'm glad that there is a website for El Camino's with experienced person's on here that are willing to teach and lead someone like me in the right direction.
 

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Now that is a much better plan, Jeremy. With any luck your engine will be in decent shape and not run up a big bill at the machine shop.
 

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I'll give you a little input from 2 305's I,ve had years ago. The factory HO heads are the best 305 factory heads, got mine from the local head rebuilding shop, mildly ported myself, & had them reassemble with 3 angle valve job. Not 100% happy with power it made in el camino with 260 comp cam & performer intake /holley like I was with similar setup in lighter chevy monza. Later switched to tuned port injection( ported) & crane dual pattern comp cam. With the tpi combo , it ran stronger on the street than the average decent 350 engine. With a 5-speed & a2.73 rear, I once ran it on a new, straight country road (undisclosed location) with the factory 85mph speedo needle hitting the stop back under the 0 & the tack passing 4,000 rpm in the .63 gear 5th with 25" tires. Do the math, that,s rollin pretty fast in the engine's peak torque zone. This engine had as much low end grunt later with a 3.73 rear as the stock LS1 that it replaced, though the 5.7 LS1 quickly outpowered it & revs higher.
Bottom line, a properly built 305 can give better street performance & economy than a lesser built up 350, but will take more effort & expense to do so. Just like any other older lower tuned factory motor , there is much room for improvement.
 

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Some sage advice posted above. I just wanted to add one comment..... Porting and polishing would deliver very little or no benefit in a non- performance motor. The benefits show up bigtime when you start turning long duration cammed motors above 5500. Aside frlm racing there is little to be gained.
Buy a nice GMPP crate motor. With a warrantee and some real power and torque. My dos centavos
 

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Some sage advice posted above. I just wanted to add one comment..... Porting and polishing would deliver very little or no benefit in a non- performance motor. The benefits show up bigtime when you start turning long duration cammed motors above 5500. Aside frlm racing there is little to be gained.
Buy a nice GMPP crate motor. With a warrantee and some real power and torque. My dos centavos
Bingo! ^
 

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X2!!!
 

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The heads on the 350 in my T are ported. Somebody before me (not sure who; I got the heads from another member, who got them from another member) had done the work. They don't do much for the engine, just a little. My engine is very mild, low compression, nothing fancy, not much cam, nearly stock in every way, producing about the same power (around 250 hp at the flywheel) as it did in the 1970 Caprice it came out of.

Tommy Ivo, in an article about him in ... I think Popular Hot Rodding magazine said that after he did head work on an engine, he could always taste cast iron in the back of his throat for a week.
 

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Tommy Ivo was right....the cast iron dust penetrates dust masks & plugs them up fairly quick. That can't be good for health reasons. My last port/polish job was on the Caddy heads for my Elco project, and I used a good sized fan on the bench to blow the dust away while I did the work. Even then, I could taste the stuff....

And I also did the exhaust manifolds, since there was no room for headers.
 
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