267 to 305 parts swap & Rebuild

[greymouser7]

Greetings, I am new to Club Hotrod -This is a great site! My name is John Anderson. I am active duty Navy. I was hoping for some advise.

Car: 80 Impala 267, V-8, 3speed auto, previous daily driver 130K miles, very slow acceleration. So far I bought a 305 block and cylinder heads.

The block was supposedly machined and the heads have the springs (new?) on them- that's all that is installed on the heads. The heads have heart shaped combustion chamber and I can look at them again tonight for specific info to any questions.

How do I figure out the cc's for the head combustion chamber and calculate for the maximum compression that I can run on either 87/89 octane gasoline?
Will the crossmember that supports the 3 speed transmission support the 200-4R I wish to replace it with? The crankshaft has the 3.484" throw that stock 305's and 350's use. Is it wise or necessary to replace the stock rods?

I want to use as many parts from the 267 to supplement the 305 as practically possible. I found on the internet that the crankshaft mains are the same large journal size. The motor still has all the smog junk on it. The rear end gear ratio is less than 3 to 1. Honestly, I have never rebuilt a motor before but am sure that I can manage. The goal is reliable transportation, significant torque, low buck assembly, and fuel economy. I am actually not concerned with horse power output. I am willing to spend decent money on a rebuild kit and machine shop work for optimum output. I am strongly leaning towards an RV cam and a 200-4R transmission. Can anyone explain the tow capabilities of a 305, 200-4R, tire size, and 2.X gear ratio combination. I realize that the 4 speed is the weaker version and that the 2.x gear ratio in the differential (10 bolt main) is the worst for general towing. Any recommendations/points of concern are appreciated-especially brand names, or rebuild kits. The small block chevy rebuild kits seem to vary significantly in price. I understand that some kits include rockers, and cams-some don't.
Thankyou all whom respond.

[techinspector1]

Hey John, welcome aboard. Pull up a chair and grab some crackers out of the barrel over there. Somebody get John a cold soda.

We'll start things by determining what variety the 305 heads are. Chevy puts the casting number where the valve springs go on the head. Use any of the several sites on the web to find information on them. I used to use Mortec all the time, but can't get it to come up for me lately. Here's another.....
http://www.73-87.com/chevy_ids/sbheads.htm

This site uses only the last three digits of the casting number....
http://www.auto-ware.com/techref/castnum.htm

Here's another.....scroll halfway down for head numbers.....
http://www.montecarloss.com/SSThunder/SBCinfo.html

If you can't find any useful information from these sites, go to google and enter the casting number and Chevy like this...
1234567 Chevy

[greymouser7]

I found the heads on your first Web site. Thanks

YEARS CASTING# CID Intake Exhaust CC COMMENTS
1980-84 14014416 305 1.85 1.5 - 4 barrel

[greymouser7]

self note- from another post and your website reference
"You have to use a retrofit hydraulic roller lifter kit from one of the major cam manufacturers. They are not cheap. A lot of people like the Isky retrofit lifter kit. You can use any manufacturer's hydraulic roller cam with it. You cannot used stock GM roller lifters in a pre-'87 block."

2-bolt blocks with OEM main bolts are good to 400hp
2-bolt blocks with ARP main studs are good to 550hp

OEM 2-bolt blocks are good to 6000 rpm.

In the Article, it stated that a 250hp engine that was spinning at 7500rpm exerted more loading force
on the Main-caps than a 550hp engine spinning at only 5500 rpm. This means power and RPM must be considered
when selecting how much beef you need in your bottom end.

[techinspector1]

"OEM 2-bolt blocks are good to 6000 rpm."

It all depends on the rotating assembly that you bolt into the block. I've heard of 283 and 327 assemblies being wound up to 8000 and even 9000 rpm's due to the short stroke. I doubt you'd ever get a 400 or 383 to that point though, without the block disassembling itself.

[techinspector1]

As far as the cam itself is concerned, it is indeed the heart of the motor. Whether you end up with a motor combination that is a pleasure to drive or a combination that you'd just as soon drive into a lake and forget it is tied directly to the camshaft.

I see this constantly with inexperienced engine builders. They'll use a long cam with the stock compression ratio and then they don't understand why their car is slower than it was with the stock cam.

Static compression ratio is directly tied to the cam characteristics.
Dynamic compression ratio is directly tied to the cam characteristics.
The torque converter you use is directly tied to the cam characteristics.
Rear gear ratio is directly tied to the cam characteristics.
The induction system you use is........well, you get the idea.

Any cam you bolt into the motor has an operating range of about 3,500 rpm's. It may be effective from idle to about 4,000 rpms or 1,500 to 5,000 rpm's or 3,500 to 7,000 rpm's or whatever. So, when you are planning the build, you need to determine the operating range of the motor before you ever pick up the phone to begin ordering pistons, heads, etc.

From your first post: "The goal is reliable transportation, significant torque, low buck assembly, and fuel economy. I am actually not concerned with horse power output."

With this in mind, I would build the motor to about 9.0:1 static compression ratio with a tight squish (0.035" to 0.040") and use a cam tied to the scr. A cam such as this.....
http://www.cranecams.com/?show=brows...tType=camshaft
or this.....
http://www.cranecams.com/?show=brows...tType=camshaft
would work well in such a motor. Read the "description" in the upper right hand corner of the cam card as well as the "Recommended RPM range with matching components" about halfway down the cam card on the right side. Pay particular attention to the "matching components" verbage. You want to use parts that will work well with the cam you choose, particularly in this day and age. Oil companies have deleted most of the extreme pressure components from their oil formulation due to pressure from OEM's and the Feds, so I'm hearing and reading about more and more cam failures. Here's a link to another CHR thread with some more information about that.....
http://www.clubhotrod.com/forums/showthread.php?t=31284

[greymouser7]

Dear techinspector1,
Can I still do 80-90mph in city/highway traffic with the low level cams that we are talking about? I know there is such a thing as valve flaoat- not sure exactly how it works considering i have driven the impala over 120 on the interstate with the rest of the crazy drivers in the fast lane and i know the cam is way economical in the 267 -what really happens at this point when you are above the cam's range? And what type of stall converter do i use? my guess is stock, which would match these cams we are entertaining.

[techinspector1]

"The rear end gear ratio is less than 3 to 1."

Let's say it is 3.00:1 with a 26" tire. Using the second cam scenario that floats the valves at 5,600 with the recommended components, the math is as follows:
26" times 3.14159 equals 81.68" tire circumference. 5,600 divided by 3.00 equals 1,866 rpm's at the tire.

5,600 divided by 3.00 times 81.68 divided by 1056 (constant used in the formula) equals terminal speed of 144.38 MPH. If you factor in some slippage for the torque converter (5%), then you would multiply 144.38 by 0.95 and find a terminal speed of 137.16 MPH.

Trust me, you won't get that speed out of a mild motor because it won't make the horsepower required to pull the car that fast, but there's the theory of using that cam.

"what really happens at this point when you are above the cam's range?"
It floats the valves and stops making any more power. If the piston to valve clearance is well thought out ahead of time when building the motor, no damage will occur. The springs will be a little weaker after they are taken to this extreme, so the next time you do it the motor will float the valves at a lower rpm.

"And what type of stall converter do i use?"
With either of the cams I posted, a stock converter will work.