2-Bolt RPM range?

undertow · 03-25-2006, 03:48:37 PM

I'm thinking of rebuilding my 2-bolt 350 but I have some questions. Keep in mind I have no experience rebuilding an engine but i'm going to attempt it. I want to bore it 30 over, have the machine shop do up the block and heads, cam, valve springs, etc.

Cam: I was looking at the Edelbrock Performer Plus Cam and was wondering if that's too much for the 2-bolt block. What's my RPM range for a 2-bolt block? I got it out of an 86 Chevy PU.

If I choose to go the Performer Plus Cam direction, what other things do I need to beef up to handle this Cam?

I'm looking to spend a little under 2K. What do you recommend? Thanks!

pdq67 · 03-25-2006, 05:38:20 PM

First, get the CR. up to about 9.75 to 1 or so! Just below 10....

Then install a 268/270/272/274 cam in it, a 750 cfm 4-barrel on a high-rise IF it will fit under your hood like a Holley 300-36 and a set of 1.625", 4-tube, long headers and a free flowing exhaust and I figure that you will be very pleased!!

GREAT powerful, daily-driver type motor that will run!!

HEADS!! And if you want to, grab a 1/4" drill and some cheap chinese stones and do a quick, valve bowl-blend machining ledge and casting flash clean-up as well as remove the casting flash/dingle-berries from all the ports!! CHEAP power production here!!

pdq67

PS., cams like these...

CC 268HE, 270 magnum and XE274;
Crane 272/272 Energizer and 274H06;
Isky 270 mega...

Old school cams except for the XE jobber that still run VERY well in a motor like this!!

GetMore · 03-25-2006, 06:21:33 PM

The stock parts will hold up to more than 6000 rpm, so you should have lots of cam choices.
Some people have spun stock, two-bolts to 7000.

Mwilson · 03-25-2006, 06:50:08 PM

I run a 2 bolt and it has lived so far. I have turned 6,800+

cody · 03-25-2006, 07:43:17 PM

yea mine routinely sees the 6500 rev limiter...been up to 6700+ a few times before that

undertow · 03-25-2006, 09:12:13 PM

cool thanks for the replies!

i did some reading on past posts where some people had problems with 2-bolts not handling the power they gave them so I wanted to make sure. I wanted to get the 290hp crate engine from gm but between you guys and my friends saying to build my existing one i thought i'd give it a shot.
what hp could i expect by doing the following?

- bored .030 over
- eddy performer intake
- 4bbl q-jet
- eddy performer-plus cam and valve springs kit
- stock distributor
- th-350 at
- machined block and stock heads

pdq, sorry to ask this but I don't know, the 9.75 to 1 is the compression? how do i achieve that?

73Z28LT · 03-25-2006, 11:09:45 PM

Two bolt blocks can handle 6,500 no problem especially if you use ARP bolts.
I have a 66 chevy II with a 327 and i could shift it 7000 all day long. To reach a certain compression ratio depends on piston and cc head selection.

camaronut79 · 03-26-2006, 01:18:41 AM

Quote:

Originally Posted by undertow

cool thanks for the replies!

i did some reading on past posts where some people had problems with 2-bolts not handling the power they gave them so I wanted to make sure. I wanted to get the 290hp crate engine from gm but between you guys and my friends saying to build my existing one i thought i'd give it a shot.
what hp could i expect by doing the following?

- bored .030 over
- eddy performer intake
- 4bbl q-jet
- eddy performer-plus cam and valve springs kit
- stock distributor
- th-350 at
- machined block and stock heads

pdq, sorry to ask this but I don't know, the 9.75 to 1 is the compression? how do i achieve that?

post the casting numbers of the heads so we can see what size cchambers it has.yes it is the compression.

Cardinal · 03-26-2006, 04:05:39 AM

All above posts give good advice.

Get the casting numbers off the heads so we can see the valve size. If they are good sized heads, you might want to consider having them angle milled to decrease the combustion chamber = higher compression. BUT, having said that, if it looks like you're going to spend anywhere near of over $400 on the heads you have, consider buying a set from Northern Auto Parts, Summit, Jegs, Speed-O-Motive, or PAW that usually have bronze guides, big valves (some have Manley SS valve too!).

79silverz28 · 03-26-2006, 07:23:53 AM

...if this is your first rebuild, go for the safer side in any of your decisions so you don't have any trouble. Better to have a little less power and a reliable powerplant than to try and get everything out of the block on your first try.

Shoot for closer to 9.5 to one, guarantee yourself no pinging on stock gas. When you get the block done, get it 0 decked, this will raise your compression to at least 9 to 1 with stock junky heads, but will most likely raise it closer to 9.3-9.5 to 1.

Whatever cam looks great, pick one size lower, you'll probably be happier.

Don't worry about revving super high, there will be other issues such as heads breathing capability and valve float from the springs in the heads. Figure you won't go above 6000 RPM and build from there, again you will be in your budget and you will be happier. Sounds like this is a street car, build in that direction first, and as a racer second.

You will be able to get the labor done for under a thousand. Get a rebuild kit from Summit or Northern or whoever you prefer, with pistons and gaskets in the kit, it should be about 300-400, depensing on if you want forged or hypereutectic pistons.

Good luck, I'm having fun in the middle of rebuild myself right now.

Mwilson · 03-26-2006, 07:26:30 AM

You need the casting # off your head so we will know your chamber cc then you decide what piston/head gasket to buy to achieve your desired compression. Or like cardinal said just buy some new heads. The smaller the combustion chamber the better I believe as apposed to higher to higher compression pistons. If you buy heads go with some 64cc.

pdq67 · 03-26-2006, 10:53:18 AM

I use the ROSS Racing Pistons compression ratio calculator to play around with finding what a compression ratio can be.

I input a -5 cc's for 4-valve stock type flat-top pistons OR whatever the stock dished/domed pistons are, a stock, down-in-the-hole of .025", head cc sizes that vary all the way from about 53 cc's, (for a 305HO, -601 head), to up above 80 cc's, (for some of the later 400 engine heads!!)...

And headgaskets vary all the way from Fel-pro's #1094 at .015" thick up through Stock and Mr. Gasket's .020" shims, then about .028" or so, .038/.039" or so to .040's(?), then .050" and even .060" and thicker.....

Have fun b/c you can mix and match to make about any compression ratio you want what with all this stuff to vary AS WELL AS use aftermarket heads and pistons sized to create it too.....

Oh, 'bout forgot, we generally like to see our quench number anywhere from .035" to .045" for best quench eff. This way you get a really good air/fuel mixture movement as the piston try's to hit the flat of the head..

And about 9.75 to a schosh under 10 to 1 is usually about max. CR. for pump gas! BUT then again, aluminum heads and cam choice and other things can be "tweeked" to up this number as Mwilson said earlier..

pdq67

undertow · 03-26-2006, 05:09:53 PM

Alright i ripped out the heads, pistons, and rods. my #8 piston lip busted off and was bouncing around the oil pan last year. i was going to replace just that piston but i had a weird feeling that that wasn't the only piston damaged...i was right. 2 other cylinder walls were scratched and another piston lip was off. anyhow here's the casting number.

#14014416

another number I found, which probably doesn't mean anything is E226.

79silverz28, that's exactly what i'm wanting. i want a pretty quick street car but not racing atm. i get grief from ricers that have more stickers than cylinders

let me know if those are good heads to play with. if not, i'll check my pocketbook and see if i can afford getting the 64cc heads you guys were talking about.

Thanks again for all the replies. asking questions and actually doing it yourself is a big learning experience. i think i'm hooked

night rider · 03-27-2006, 02:13:53 AM

Those head casting #'s are for a 305 HO head.

14014416...80-85...305..........HO, 58cc chambers, 1.84"/1.5" valves

pdq67 · 03-27-2006, 08:21:39 AM

They probably made too much compression for you? Depending on your piston type. Rattled her and got the top ring lands!!

Like I said, use onna the cams I mentioned with your CR. where it needs to be and you will be fine!!

Great running 350 street motor!! Imho...

pdq67