I have some questions on 305 ci motors. I have a 77 4th gen nova with a 305 and want to know if this motor can be made more powerful and is it worth dumping money into? Also there is not much info on this engine or rather I haven't found it. (directing me to this info would be great) I know a 350 is what everyone has. I just want something different.
  Whats the difference between a 305 and a 302 sb.  And, what late model automatic trans w /od will bolt in with this engine with the least cost and mods? This is going to be a low buck project with lots of junk yard parts. So any help will be greatly welcomed. I am wondering if the parts concidered in this month's junkyard crawl artical from 94 to 96 police caprices will swap to my 4th gen nova? thanks.  

Do a search of the Forum the build/don't build a 305 topic has been throughly beaten and opinions about the engine run rampant.

The 700r4 and 200r4 will bolt to the engine and if you have a TH350 already then I hear the 200r4 will bolt in with just a slight cross member modification.  

Basically what I gather is just about anything you bolt to the 305 will bolt to and do better on the 350 (or your choice of small block). So you can always buy some good parts for the 305 and eventually get another short block altogether and move your upgrades over.  

There is a reason why you have to be "different" if you want to build a 305, it's because nobody else is using them! Being different just sometimes is not the best way out for average joe hot rodder. Short of putting in twice as much money (or twice as much nitrous) as a "regular" mild, street performance build there really is no way to make a 305 outperform a 350. If you want to stay as cheap as possible and just have a car that drives and will chirp the tires by all means do a stock rebuild on the 305, but don't make it into something that it's not, a performance engine!

A 305 and 302 are night and day different. The 302 was a late 60's and early 70's PERFORMANCE engine. It had a big bore, short stroke, long connecting rod, high compression, and big valves. The 305 was a 80's SMOG engine with a long stroke, small bore, small valves, and relatively low compression. You cannot make a 305 into a 302, you can't make a 305 into a 350, you can't even make a 305 into a 283!  

These last 2 statments are very correct.I currently have 305 in my truck and if you want to compete with a 350 you need to 1:spend a TON of cash or 2:get CUBES.there is no replacment for cubes.My 305 will get right with the program because I spent a little time tweekin the thing but it was a healthy"FREE" engine for my truck till my 454 is complete.So if 4 the fun,go 305,but to beet bigger engines you better have it together on the tuning side and sum bottle to back that up.  

I have a 305 TPI in my IROC.  Its fun...the TPI gives it great throttle response...it has decent torque for as small as it is...and runs fairly well.  It is NOT powerful.  I put quite a bit of money into it without much in the results department.

There are ways to make them better...but in all honesty whats the point?  It looks exactly the same as a 350 or 383...so why not get the performance to go with it.  If you want something odd ball then a 302, 327, or a stroker combination other than 383 would fit the bill and still give you better performance.

But if you are dead set on using the 305...here is how I would do it

Short block: basic rebuild with forged pistons
heads: 350 vortec castings milled down to give an acceptable compression ratio (apparently the 305 vortec castings do not flow well at all)
induction: Edelbrock TPI runners with vortec base (you can find a complete TPI unit for not a lot of money on ebay and it should help boost torque on the low end)
And then add a vortec supercharger...
camshaft: nothing over 220 degrees duration at .050 and make sure its got a wide LSA
exhaust is whatever you'd like...

without the supercharger you're dealing with a mild small block that will push a camaro into the low 14's high 13's.  Supercharger will help a lot...but thats a ton of money to spend on a motor that is completely maxed out...especially when for the price of the supercharger you can have a well built 350 or 383 short block delivered to your door...  

Wow guy's I guess I asked for it. I have been out of the loop for a while. I haven't put any money into this motor yet and from the sounds of it I probley shouldn't. But for now it run's and I hope to at least make the local cruise nite once or twice.I sure welcome the info thanks Kenny.  

That's my favorite method for upgrading cars, drive it, improve something, drive it more. With every tiny improvement you get more enjoyment out of it.



(Hell I am estatic I got the vacuum power door locks working on my T-bird this weekend, it doesn't take much as long as it's progress)  

the.chev 305 is a good engine most 305and350 parts will interchange. you can get 300 plus hp from a305 at a resonable cost most chevy transmissions will interchange 305 and 350 is the same block. 350 has a larger bore (4.00) good luck  

If you search online for 305 performance you should be able to find an article from chevy high performance where they built a 305 camaro. It is a very interesting article. The 305 isn't a bad engine, but it makes a high pro build difficult. One of the things that works very well with it is a blower or a turbo. It will be a very torqey engine, and performs very well for street. If you want to race that is a different story.  

I also forgot to mention that the 305 is great on gas. I built one for kinda the same reason as you. I ported the heads my self and it performs very well. What ever you do stay with intake valve less than 2.00". The bigger valves shroud really bad and you will most likely loose power.  

try www.goingfaster.com. i found their article on the 305 and saved it to my favorites on my computer, b/c i own 4 305s. 3 of them were free, and the 4th one was salvaged from an 80s caprice. if you stay with the 305 (or 350 later) find an 80s or 90s car with the already mentioned 700r4 or 2004r trans. im actually getting ready to drop a 305 and 700r4 in an 84 s10 cuz the it was all free! i just get to put it all together  

4thgennovanut:
I have some questions on 305 ci motors. I have a 77 4th gen nova with a 305 and want to know if this motor can be made more powerful and is it worth dumping money into? Also there is not much info on this engine or rather I haven't found it. (directing me to this info would be great) I know a 350 is what everyone has. I just want something different.
  Whats the difference between a 305 and a 302 sb.  And, what late model automatic trans w /od will bolt in with this engine with the least cost and mods? This is going to be a low buck project with lots of junk yard parts. So any help will be greatly welcomed. I am wondering if the parts concidered in this month's junkyard crawl artical from 94 to 96 police caprices will swap to my 4th gen nova? thanks.

How many miles are on your engine??? I mean if your engine was stock and you don't want to swap it, Edelbrock makes complete lines of street and strip perfromance parts as well as many other companies. If you got like 50000 miles or less, I'd say build on it until it blows up. Then buy a crate engine. Here's why, the 305 is just like my 267 in my Malibu on the bottom end. It has the same crank, rods, main journals, and journal diameters as a 350. I don't know why chevy SB's with under a 4" bore don't flow well, but you can make the engine more peppy for the street at least. Try to get a hold of an old Chilton manual, or stop in at a parts stores and see if you can find a Haynes manual. These rebuild manuals will give you some specs of your engine, and show you exactly how to disasseble and reassemble the engine. They usually run around 20 bucks. If you want to dump a ton of money into it, put a 400 crank in it and bore it out .030". This will give you 334 cu. in. Of course this is REALLY expensive as the engine block needs machining for lobe clearence, and the crank MUST be externally ballanced by a professional machine shop, unless you knowhow to do all that stuff yourself. I mean these are just some options. If you wanna go fairly on the cheap side, an Edelbrock Performer Series 500cfm 4-barrel, with a Performer Series manifold #2101, a set of small to mid-size headers, and dual exhaust will give a noticeable perfomance gain in both low-end torque and high RPM HP. I would say minus your catalysts, SMOG conrtrols and your AIR pump, you might see 35-40 HP, and much more torque. I only suggest these produacts as that is what I have already started my 267 with these(Execpt I used a #1406 600 cfm carb) and have had decent gain over stock performance and increased my fuel economy a little bit also. A performer series cam with a 204 in. and 214 exh duration at .050 should help wake it up too. This cam is designed for street use and is 50 state legal, if emissions tests are mandatory. For the transmission, you can greatly increase your fuel economy by swapping to either OD. They are both more agressively geared in 1st, and 2nd. This will also increase your lateral acceleration as it'll turn the driveshaft faster, and you'll benefit from the highway gear. You can find more information at www.700r4.com for the transmissions. Remeber if you build it and it blows, buy a 350 crate engine and throw the bolt-on and such into it.  

I was inspired by several articles on Chevy 305s, Car Craft featured an 80s Camaro in 93, I believe can be found on goingfaster.com.  

Here's what I did for my 305.
Purchased a set of 416 casting heads from ebay, pocket ported, and treated the intake valves to a 3 angle valve job.

Replaced the dished pistons with flat top, 5cc valve reliefs

Cam - Comp Cam 224 duration @ 0.050" lift, advanced 4 crankshaft degrees.

Edelbrock dual plane intake

1 5/8" headers with 2.5" dual exhaust

stock ignition with MSD coil.

Carter AFB 600cfm carb, Edelbrock's version will do the trick as well.

I have this combo backed up with a turbo 350 in my 74 Nova with stock gears and stock converter.

The car has turned 14.8 @ 94 mph.

This combo won't blow the doors off, but this was my first motor build and if I blew it up, no big loss. If I had to do it again, I would use a smaller cam, its pretty lazy from idle to about 2500rpm.  Next spring, I plan to to change the ignition curve, increase the cylinder pressure at the bottom end, will keep you posted.

I was fortunate that it was a low milage motor (32K) and I just honed the cylinders when I swapped pistons.

Lou  

http://www.goingfaster.com/spo/343hp305.html