Small block power

[Bulldog]

I am going to start building my 85 half ton up to be a wheeler. It currently has a 305 with what looks like a blown head gasket. Trying to decide whether or not to just replace the head gasket or upgrade to a 350. If I go with a 350, I would have to change out the 2bbl carb for a 4 bbl also.

Here's the plans for now. Install 3/4 running gear with 4.10 gears and 33" tires for now with 35's in the future. It has a SM465 and a NP208. With the low diff gears, the low first gear in the tranny, and the 2.8 to 1 in the transfer case the 305 SHOULD have enough gusto to keep it moving through the mud and climb the steep inclines. What do you think?

[ChevyKev]

1. If you went 350 would it still be IM'able?

2. Yes, especially if you build it mildly. One thing a 305 has over the 350 is higher compression. Many folks take 305 heads and place them on 350's for that very reason.

3. I had a 305 that was worn out in my Vega for a while and it did great. Put in a fairly fresh 350 (fresh, but stock and probably only about 220 HP) and really didn't find much a difference in the power - measured only by seat of pants effect as copmpared to a dyno, but I really couldn't tell I had that much more power. While a Vega has much less weight, your gearing should help the 305 out.

4. If you are in fact looking for a 350.... I happen to know someon who has a few!

[Bulldog]

1. If you went 350 would it still be IM'able?

2. Yes, especially if you build it mildly. One thing a 305 has over the 350 is higher compression. Many folks take 305 heads and place them on 350's for that very reason.

3. I had a 305 that was worn out in my Vega for a while and it did great. Put in a fairly fresh 350 (fresh, but stock and probably only about 220 HP) and really didn't find much a difference in the power - measured only by seat of pants effect as copmpared to a dyno, but I really couldn't tell I had that much more power. While a Vega has much less weight, your gearing should help the 305 out.

4. If you are in fact looking for a 350.... I happen to know someon who has a few!

A 350 was an option for this year and model, so it should still be I/Mable.

I figure head gaskets would be a quick and inexpensive fix, but I'd hate to waste time and money if I'm dissapointed and want a 350 after fixing the 305.

I have a 327 I could put in it (may not I'M though), but I am saving that for an Olds F85 I'm going to build up this winter, unless I find a 455

If I plan on changing the head gaskets, do you think I should throw a cam in it? Got any recommendations?

So far, the trail rides I've been on have been low speed, not needing too much power. A lot of first gear and low range. Although, the mud on I saw on the trail off of Repp road did need some RPM's to keep the tires cleared though.

PM me a price for a "gently" used 350, complete with intake and carb. Would need to be I/M legal for an 1985. I should be able to use my exhaust manifolds and other accessories.

[ChevyKev]

..................................... I have a 455!

I also have a BOP cased 350 turbo trans - newly rebuilt!


but the 455 is a Buick, not an Olds. :whistle:

bored .060, port and polished heads, huge cam... I really need to put that in something! :headbang:

Will work on a PM shortly.

However... head gaskets really aren't that difficult of a job. So you spend $100 and 4-6 hours, that's really not much to get it up and going soon. Then if you want a 350 later you have a running/sellable 305.

I've never "built" a 305, so as to what cam you would want to throw in there, I'm not 100% certain. I know an inexpensive upgrade to the 350 is the "RV" cam, but I'm not sure if that would be a good upgrade for a 305. The RV cam is designed for more lower end torque for pulling... an RV. I have to stop by Port's machine shop this morning, so I'll ask them.

I'll also work on a PM.

[ChevyKev]

According to my friends at Port's machine shop, the smaller cub inches a motor is, the more noticeable a cam is. Since small block Chevys can use the same parts, you would notice more of a difference using the same cam in a 305 than a 350, and more noticeable difference in the 350 than a 400. They also said an RV cam would work well in a 305.

On another note, for $220 you can get a set of roller rockers that are a bolt on 30hp (provided you have the right heads and don't need to buy guides as well, still doable but for a little more dough) They said that a set of roller rockers would be as much of a noticeable gain in power than a cam.

Combine the two...

[Bulldog]

So many options. If I threw enough money at it, I would have nothing to worry about. I like the thought about combining the RV cam and the roller lifters, but then you'd have the heads re-built also. Then you might as well put new rings in.

Ever hear, "Give a mouse a cookie....":p

[ChevyKev]

My son Kael wrote a story a few years ago - he was 6 -

"If you take a boy to NAPA..."

[sevenslats]

I'd actually like to hear that sometime.

My kids have If you give a moose a muffin and If you give a mouse a pancake and love them.

:topic:

[ChevyKev]

HE made it into a little book, Kris has it somewhere...

Now back to Chevy Small block power....

I think I mentioned that some folks have used 305 heads on the 350 for the higher compression - but what exactly is the result of doing that? Bueller? Bueller?

OK, besides higher compression....

What is the effect on HP?
Torque?
Better for top end or bottom end?
What about a 383 with RV cam, roller lifters, and 305 heads?
WHo actually knows and who's guessing?

I'll do some research...

[ziggy]

Most 305ci cylinder heads are 54/64 CC, As the 350 are useualy 74 depending on applacation there are alot of heads out there to genralize the 305 head.
Changing the stock 350 heads out with run of the mill 305 54cc heads realy made little to no Seat of the pants change for me. Free flowing exhaust how ever made a rather large notice at the PUMP! For the better.
I recomend keeping it stock and running good and dependable Upgrade to some roller rockers,Better intake system and exhaust. And for a bit more dependablility Holly/Edelbrock MPFI conversion I scored one for about $900 NIB.
My $.02

Anthony

[ChevyKev]

Good stuff - info from someone who has done it!

I do know a stock car racer that swapped 305 heads on so that he runs a bit cooler, as overheating is a common problem. He claims to be running about 20-30 degrees cooler than the others.

[ziggy]

so that he runs a bit cooler, as overheating is a common problem. He claims to be running about 20-30 degrees cooler than the others.

:nerd: Hmmm. Thats strange but interesting.Slightly bit higher comp but over all about the same area cylinder head {cast iron} Would think with higher comp the heat would be increased unless using a aluminum head.
I was quoted by "Edelbrock" and "BeCool" That there products were going to reduce the under hood and engine temps greatly......Even using Ceramic coated headers on the aluminum heads with 2.02 Valves and the big "BeCool" radiator and duel electric cooling fans the average temps remained the same.