[chrisflock]

I recently scored a 305 chevy, from a mid-eighties boat (the guy said it came from either a Caprice or a Catalina). We've tore the motor down to clean it up, and it's cleaned up pretty nice.

It has an aluminum intake for a four-barrel, although we don't have the carb, and it doesn't have the distributor. The exhaust manifolds I think we'll just toss, since they have the stupid AIR ports on them, but everything else looks to be in real good shape. The guy we got it from yanked it from the car because the car was about totalled, but it ran great, and he said he just didn't want the perfectly good motor to go the junkyard and rot.

So, what can be done to make this engine rock? I'm thinking of using it to replace the tired 305 in my truck, but I don't know exactly what I can (and should) do to make this engine have some more pep.

The pistons look pretty darn good, and the rings seem to seal pretty decent. All of the rods are tight, so we were thinking maybe we shouldn't mess with the bottom end. It was a low mileage motor, something like 60 or 70K, we only tore it down because it had been sitting out of the car for a while and we wanted to get all the sludgy oil crap out of it.

We don't really have a lot of money to spend, but we would like to get some solid torque of it for my truck. My truck has a 4-speed stick, and it will have something like a 2.93 rearend, so I'm looking for some more low-end grunt.

I wouldn't mind getting an intake and a set of headers, the only worry is I don't know if I can score a nice carb on the cheap, and my truck is currently TBI. I also don't know if I should plan on using the TBI set up. I could get a set of Vortec heads for this 305 from another 87 truck, and the intake and TBI system. However, I would much prefer to get a carb on it.

I've been told that getting an adapter plate to put my TBI on a nice edelbrock intake should make some nice power.

And please, nobody tell me to just get a 350, unless you have one you want to give me or somewhere I can get one for 20 or 30 bucks that's in pretty good shape.

Ooh, one more thing. I've always wanted to offset grind the crank on a motor. Are there some stock con rods that could be used for this idea, or is this going to be something totally not worth the effort and money? If this would be doable, I could have a nice stroker that should make a lot of torque.

Or should I look towards boring? Can these motors be bored enough to take 325, 307, or 327 pistons?
Can these engines be bored out enough to make it worth the effort? I have been told by some people that these 305's have the same block as a 350, just not bored out as much, but others have told me the waterjackets are thinner, and that boring it out that much can leave the cylinder walls to thin. Is this true?

Any constructive ideas would be appreciated.

 

[mikeweyman]

go to the scrapyard and get a set of 416 casting 305 high output heads .add in a good cam and you should wake the old girl up. i bought a set for 20 bucks.mike

 

[DoubleVision]

Use the heads mentioned above, I`d have them milled about .010 to raise the compression ratio slightly, and I`d use a GM head gasket. I would replace the camshaft and lifters, and add a new double roller timing chain, the Edelbrock performer cam will suit you fine, but summit carries a cam and lifter kit of the same specs at a price of $80 for both. I would get a Rochester Quadrajet carb, keep your stock intake, add a set of small tube headers and dual exhaust, other additions I would add would be spiral core spark plug wires, and a K&N filter. Offset grinding the crank is a waste of time and money in your case, and no, a 305 cannot be bored to a bigger small blocks bore size, most don`t recommend you bore a 305 more than .030.
The 305 and 350 share the same 3.480 stroke, the 305 has a 3.736 bore, while the 350 has a 4 inch bore, hence the cubic inch difference. The combo I mentioned above will give it good torque and gas mileage.

 

[BlownBirdy]

305

not sure if you can use 302-327 pistons but I got a set for my stroked 305 (334) from keith black for about 220 bucks from summit a few years back. I have built two carbureted 305's, one a stroker and one with a factory stroke. You won't get more than 400 horse out of it naturally aspirated so don't kill yourself trying to find a combo that turns your vehicle into a track star. I run a Road Demon Jr. 625 carb that i got brand new on ebay for 250 bucks. I love it. If in the search box up on top your type in 305 pep the first thing that should come up will be a post titled Need help giving my 305 a little more pep. In that post i list in detail everything my 305 has. It's a fun engine to toy with but if you want power you need more cubes. I run World Products S/R torquers with a professional port and polish and milled slightly to bump up compression. Not sure if you want to spend that kind of money though.

 

[chrisflock]

what years/models might I want to look for to increase my chances of finding 416 heads?

There aren't many good junk yards around here, so those may be hard to find. Might I be able have the heads i've got milled down? I'm afraid of bumping my compression too high, as I don't want to end up having to run real high octane gas.

What about using vortec heads, will that make more power? I should be able to pick up a decent vortec intake for not too much money, especially if I can find someone to trade for my aluminum standard intake. I did get a rochester four barrel today, i traded one of my cousins a potato gun for it. I'm assuming it will need a rebuild, but that's no big deal.

Do you happen to recall the name of the Summitt cam? Also, I'm going to need a distributor, any good pointers there? Or can I use the current distributor? I've noticed it doesn't have a vacuum advance, I assume because the computer controls that on these fancy fuelie motors.

Chris

 

[strikingthematch]

Hey Flock,
I have a set of 416 castings that im looking to sell. They are in good shape and I have the valves and springs that go with them. I got them a month or so back at a junkyard. Took them home and cleaned them all up. I have pictures and such of them. Contact me and maybe we can set something up.

Chris

 

[chrisflock]

What is different about these heads? are they better than vortec heads? Do they just have higher compression than stock. I would like to get them local because of shipping, since I would imagine that would be something around 120lbs. Of course, if the price is good and shipping isn't too bad, then that would be great.

Chris

 

[strikingthematch]

Main reason these heads are good is because of the 58ccc chambers. It really helps to up the compression. You can use the compression cal. on this site I believe it's in the knowledge base to see how much it will up your compression from the current state. From what I understand they are pretty good heads while im sure vortech heads will flow better they also cost more. So in the long run it might be better to just use a set of heads like these that will flow ok and up the compression. I guess it all depends on what you want to do.


Chris

 

[chrisflock]

If the vortecs flow better, then I think I'll use those, since I already have them. I have been told that I can use a regular intake with the vortec heads, only I have to use a special 'space gasket.' Is that true, and if so is that just a recipe for problems? As near as I have been able to find, the premo on vortec intakes is only about $10, so that's not too big a deal if I have to find a vortec intake.

Also, where will I find the casting number on the heads that you are referring to? I was looking at a different set of heads today, and all I could find was a GM35 and then a real long number, which I assume is some kind of serial code.

 

[killerformula]

Re: 305

not sure if you can use 302-327 pistons but I got a set for my stroked 305 (334) from keith black for about 220 bucks from summit a few years back. I have built two carbureted 305's, one a stroker and one with a factory stroke. You won't get more than 400 horse out of it naturally aspirated so don't kill yourself trying to find a combo that turns your vehicle into a track star. I run a Road Demon Jr. 625 carb that i got brand new on ebay for 250 bucks. I love it. If in the search box up on top your type in 305 pep the first thing that should come up will be a post titled Need help giving my 305 a little more pep. In that post i list in detail everything my 305 has. It's a fun engine to toy with but if you want power you need more cubes. I run World Products S/R torquers with a professional port and polish and milled slightly to bump up compression. Not sure if you want to spend that kind of money though.

Just a couple of things...

First, you're not going to get more than 300 horse out of a 305 without some decently big dollar parts and a good tune. Sure sure sure, I've "heard" about everybody's budget hotrod 305, but every time I go to the track, they're all running in the 15's just like normal.

Second, how did you get 302/ 327 pistons for your "stroked" 305? Boy, it must have taken a **** load of pounding to get those 4 inch slugs to go down in that 3.72 inch bore!

K

 

[Mad Maggot]

I agree with killerformula, getting more than 300 horse out of a 305 will be tough, you would have to buy expensive parts and rev the crap out of it to make respectable numbers. Here's a link for a great 343 HP buildup of a 305 that might be worth checking out, however.

http://www.hioutput.com/tech/343hp/343hp.html

The heads they use are the 14014416 casting, which has already been mentioned. They just did a little pocket porting to them to increase flow. If you are interested in doing your own port work, visit

http://www.sa-motorsports.com/diyport.shtm

I happen to have a set of these heads on my 350 that flow enough for 400 horses after the huge amount of grinding I did to them. It's a really cheap way to get some extra power if you have some time to kill.

 

[BlownBirdy]

killer

Just a couple of things...

First of all, I didn't say I crammed 302-327 pistons in my engine. I said "not sure if they will fit." I don't know the size of every engine bore so i didn't want to throw out B.S. The pistons I used were the KB186 334 pistons. Made to fit in a 305 bore of 3.766 (Not stock I know. it is .030 over). Just because it isn't a 383 does not mean it is not a "stroker" either. Same crank as a 383 as I recall.

Second I never claimed that I had a 400 horse 305 or that my car was a track star. Did I????? I don't want to sound pissy but I don't recall making false accusations and I don't enjoy being ridiculed for giving my thoughts

 

[NXS]

Any ways this guy mentioned boring a 305 to its max.What is that max?

Putting a 400 crank is cool but the 305 already has such a large stroke to bore ratio as it is stock... it's got to be hard to get any real RPM out of it like that.

The 305 is lacking in the bore department, not the stroke.(I know a little about the science of it but I've never even once built a 305).

anybody here ever maxed out the bore on one?

 

[killerformula]

Max overbore isn't too aweful much, not more than .040 or .060 in most cases.

Birdy, chill dude, I'm just clarifying your post. Go back and re-read what you wrote, its pretty easy to see how "not sure if you can use 302-327 pistons but I got a set for my stroked 305 (334) from keith black for about 220 bucks " means "I put these pistions in my motor"

And anyway, this has been discussed to death on this board, but for the difference in cost to that of power, I would never build a 305. Unless I just wanted to freshen up a motor I already had and really didn't need a whole lot of machine work, and it was just for a daily put-put car that I wanted for decent mileage, I wouldn't bother with a 305. If your endgoal is performance, building a 305 is probably the biggest mistake you can make.

K

 

[TurboS10]

I like the combo that DV outlined. It should make for a peppy low end engine which is what you want on the street. The Vortec heads will flow more, but flow numbers are not everything. The Vortecs are really a little large for a 305 unless you are going to try and run a large cam and turn some RPM. The small port 305 heads will make for good air velocity in the low RPM which leads to good torque opportunity with the right combo. I would add that a Performer RPM intake and a smallish Holley carb would top off the combo nicely. You dont want to go over 600cfm for what you are doing. The TBI would work, but with a modified engine you will need a custom chip.

Also, it looks to me from your post that you have torn down the bottom end already. While it is apart, you may as well drop in a new set of rings an bearings. They are dirt cheap and will insure you dont have problems. You will also need to hone the cylinders to get a good seat on the new rings. It would not be a bad idea to have the cylinders checked for taper and wear just to make sure all is okay before going back together with it. It is always cheaper to check this stuff up front than to find there was a problem later and having to do it anyway.

Chris