El Camino Central Forum banner

1 - 8 of 8 Posts

·
Registered
Joined
·
86 Posts
Discussion Starter #1
Will be rebuilding a donor 305 block soon and doing crankshaft, rods and head " polishing" for the first time. Going to deburr outside of block also.Has anyone done this before?? Any noticable performance gains?? Any tips? I got the idea from next door neighbor , then found this site:
http://www.hotrod.com/howto/7234/
Any feedback is truly appreciated!
 

·
Registered
Joined
·
5,048 Posts
Polishing what, the ports on the head? Sorry to say, you will notice little if any performance gains with these modifcations, unless you change to a lot of aftermarket parts. Why not just get a 350 from a boneyard and put the money for the rebuild into it along with a dual exhaust system.

__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
 

·
Registered
Joined
·
86 Posts
Discussion Starter #3
yes, will be polishing ports... i guess you would call it " gasket matching" more than a professional port and polish. A friend donated a 305 block , so i have decided to utalize what was given me freely rather than spending 300 bucks on a 350 from a wrecking yard. I am a man of few dollars so i am doing the few things within my ability to make small performance gains. If interested i could send a few links as to what i am considering doing. IF one can believe the " independent lab" tests there are performance gains to be had. Did you check out the link i posted?
 

·
Registered
Joined
·
5,048 Posts
That's a good article if your building an engine that's going to be hitting 6500+ RPM, but a bone stock 305 is not capable of that high of an RPM. Take a look at your (stock?) exhaust pipe, what do you think your gonna exhaust through that golf ball sized pipe. The cylinder heads have lil tiny itsy bitsy valves in them, you can port those heads big enough to stick your you know what in, but you ain't gonna get poop in or out of those cylinders with those lil valves and that stock camshaft.

__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
 

·
Registered
Joined
·
2,921 Posts
When I built the 383 for the 76 I deburred the outside of the block, smoothed the inside, painted inside for better flowdown of oil, balanced the rotating assembly. It is not a tough job. http://www.angelfire.com/tx4/Warped/76elky.html#NEWSTF << at the bottom of the page are pictures of the engine in various stages and completed.

I would suggest that you look into getting a better set of heads for your 305. Look at some good heads and look at the ones that came off that 305. There are some major differences. Nothing you can do to the ones you have will make them good. Even built up the best carb match up would be about 550 CFM anything else is just too darn much for that tiny little engine.

Vortec Heads and a better intake will help a lot. Good luck on your project I hope it comes out the way you expect it to.
 

·
Registered
Joined
·
86 Posts
Discussion Starter #6
Thanks for the info Pete.... you sound very knowledgable. Let me paint a bigger picture and maybe you can offer some sound advice. With this rebuild i am planning on adding headers, a ( slightly) more performance cam and i already have a great intake.Now keep in mind that i am building an everyday driver... not trying to make a muscleblock out of a 305. The heads were redone < 20K ago so i was figuring on saving money not having to rework heads. The valves are 1.84/1.5. Whats your take on this combination? I will also be removing the flex fan and replacing it with an electric fan.
 

·
Registered
Joined
·
2,921 Posts
80Caballero said:
Thanks for the info Pete.... you sound very knowledgeable.
:oops: Shucks... Really I'm not. Just someone like you that did it. It just takes a lot of knowing what you really want the end product to come out being. What makes you itch or sweat or smile. I read,, asked questions, read some more then just spent the money on canned products that I was sure, combined, would put me in the range that I wanted to be in. And they did too! :-D I'm not saying I didn't learn a bunch.

I had a 305 in a 91 Caprice that really made me think differently about a 305. It had power and good torque, great throttle response and I drove the socks off of it. I got rid of that car it had over 160,000 never a problem with the power plant. I have a 305 in my 93 Silverado. I have over 175000 on it and the engine is still good. I don't like this version of the 305 I have to say. It is slow and slow and slow. Poor throttle response and it is slow. But on the other hand it has pretty much been 175 thousand trouble free miles. It is still a good engine, doesn't use oil, doesn't get really hot just keeps on going.:-D SLOWLY

Sounds like you'll have a good daily cruiser. The 80 models are not that heavy really so the 305 worked well. Over drive? If you could scavenge the fuel injection off a caprice and the harness + computer you could have a more managed system. I know that they give good response in the Seat of the Pants feel.

Headers always seem to help the engine breath better. Electric fans will give you back about 10 maybe more horses. There was an option offered in 85 on the Camaro it was on the special high performance package. GM used a 94 Amp Alternator. You can get these at Auto Parts stores. Direct fit with no modifications. Everyone needs a little more power for spark management and general everyday business of running the car. With newer Electronics and such mods, like electric fans, Stereo Amps, you'll need to go to a bigger Alternator.

I wouldn't go over about 600 CFM Carb it will not need it. If you can replace the Catalytic converter with a newer open element that will help too.
 

·
Registered
Joined
·
5,048 Posts
Now I think your on to something. How bout doing a lil work to da distributor, like bumpin up the voltage. I'd still change those heads to some 2.02/1.60 64cc when you got the cash. Look for a set of cast iron heads at a swap meet, shouldn't run too much. The heads you've got now will be alright for now, but keep in mind they probably have pressed in rocker arm studs and that is a weak link in your valvetrain at higher RPMS. You gotta let them breathe.

__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
 
1 - 8 of 8 Posts
Top