Suggested stall for converter
 

I was wondering what the general referances are for a stall converter for my little 307ci build. Its 30 over with a small cam. The machinest and guy that ordered my parts said to use a Z28 converter. Best I recall he said 1600-2000. I will post the cam specs from the card.

That is a pretty big cam for a 307...a lot more than I expected to see when you said 307 and small cam. In a 350, you'd probably want a 3000 rpm stall for that cam. What kind of compression are you running? What is the gear ratio?

Another gear head buddie of mine said the same thing. I told the motor guy that I just wanted a mild bump up from stock. The comp ratio is still same as stock. Not sure of the gear ratio. The car most likely still has the same gear that came with the PG and 307.

That's just a nice step up from a stock cam. I'd look for a 1800-2000 converter for it just for some added performance, but I bet a stock converter will work fine. Who makes the cam? you can compare the specs on it to comp cams with their online cam suggestion guide to give you an idea of the converter you want to use.

Rattler, Thanks thats a bit of a releif. I was thinking this was a huge cam with no vacuum for street driving. Just a bump up from stock was all I was looking for. The cam is a Erson #E110044

Your vacuum will be lower then normal and it will have a noticeable idle, but should be nice in your setup. If you can go up a bit on the converter it would help out.

230/230 is the same thing as an old school comp 280H Magnum cam, but your cam looks like it is on a 108 LSA instead of the 280H's 106 LSA. Comp's website says

"Hydraulic-Great for Street Machines. Needs stall, headers & gears. Rough idle."

Now my thinking on this is that you're sticking it in a 307. Cams act bigger in smaller engines, right? That means it will be choppier and have less "manners" in a 307.

I'm saying that the cam isn't optimally matched to your setup. When most people talk sbc cams, they refer to them by the advertised duration numbers. Yours is a 292. When I thought of a small cam for a 307, I was thinking 252. There are about 10 cam sizes in between those two.

You can put together a small inch smallblock with a biggish cam, but you need enough static compression to make power with it. You may be around 8.5:1. The more duration, generally the more CR you need. It is a 292 cam, this is what Isky says about their 292 cam...in a 350

"292 Mega Hyd.
Compression Ratio: 10-11:1
Rough Idle
RPM range:3000-7000
recomended gear ratio: 4.11/4.56
Carburetor rating: 650-780
Combination Hi-Performance Use/Bracket"

A stock cam for a 307 probably has specs something like this:

Duration @ .050" = 190°/190°
Lift @ .050" = .390"/.400"
LSA: 114


Look at this page, it calls out the specs on your erson cam...

http://www.pbmperformance.com/store.php?catId=327

All the sbc cams above it are smaller. I'm not telling you not to put it in, I'm saying that it isn't small.

Thinner head gasket?

That will help a little. Do you know the casting number on your heads?

Not sure of the number. The machinest looked at them and told me they were stock for the 307= small. Im thinking I may just belly up for a comp cams 268 duration. Anyone interested in a Erson 290?

There are other cam manufacturers and grinds. Do you want some help picking one? I'd like to help if you're interested.

YA, I would love your suggestion.

It would help to know what casting the heads are. The numbers are easy to see, they're right on the top side of the heads in between the rocker studs...usually a 7 or 8 digit number.

Later I will be able to spend some time on this.

Here is something more fitting...

http://www.summitracing.com/parts/HRS-112561-12/

Thanks. I will try and get that casting number tonight.

Got Em!
 

Took me a bit but I was able to take a peek at those numbers. I found a seven digit number upside down on both heads that was the same in the location you described. The number is #3986339

http://i165.photobucket.com/albums/u...esmotor027.jpg

.Those heads are smogger heads, designed for fuel economy, and emissions compliance. Just like the 307 itself, they aren't performance pieces by any stretch of the imagination. They have 74cc chambers, and give your 307 a very low compression ratio of roundabout 8:1. Make no mistake, the thing will run with those heads on it, but for a few bucks...say maybe $400 or so, you could be in much better shape with a different set of heads.

Your engine would have been very very very very lazy with that 292 cam in an 8:1 307.

Sounds like it will run god with some nitrous to bring up that compression when I need to pass a truck! haha
I just wanted to refresh what I had. And fuel economy is a consideration, since this will be a daily driver. My cam choice is mostly for some lumpy sound.
Still think that link to the Summit cam is the way to go?

This is a tough one, man. You're going to have to make a compromise. That lumpy or lopey sound comes from a long duration, big overlap, and quick closing lobe ramps. Usually that means that an engine is built to start putting on heavy duty power well into the RPM band, say upwards of 3000 rpm....and typically equipped with a big stall and tall gears.

The intended use of your car is to daily drive. You don't want a big lopey cam for this. Well, let me ask instead of assume....

Which do you want...

A 307 that is a dog...absolute DOG that "sounds" like it is mean but can't get out of its own way

-or-

A 307 that when you mash the pedal, the car actually responds

???

That sound you're looking for, usually means that the engine is over-cammed.


That Howards cam I linked from summit is still a good choice. There are others though. I suggest a cam on a 110 LSA or 112 LSA, and advertised duration around 250 to 260.

Here are a few to look at....

http://www.summitracing.com/parts/SUM-1101/

http://www.summitracing.com/parts/SUM-1100/

http://www.summitracing.com/parts/SUM-1787/

http://www.summitracing.com/parts/ISK-201256-262/

http://www.summitracing.com/parts/ISK-201256/

http://www.summitracing.com/parts/LUN-60100/

I see what your saying about idle. The first two cams listed seem right up my alley. They make power right from idle to 4800. The price is great as well. My goal is just to have a good running , reliable motor to hold me over untill I can put together a serious motor. If I ever make it to that point.
Of those two, which one would be better suited for my app? Thanks very much for your help.

I'd pick the second one. The tighter LSA will help keep up cylinder pressures..and possibly give you a *little* thump on idle. Plus, it will probably work with stock springs...both size and pressure. Make sure you buy new lifters (the cheap Howards lifters from summit), and run a designated, by the book break-in and you should be good to go.

You won't need a bigger than stock converter with that cam. :D

The whole motor is already together. We used Z28 springs on the valves. the motor kit came with all new parts. So I will have new lifters as well. Thanks for your help.

You're welcome. :D:D:D

Jake, Im ready to pull the trigger on the new cam. I ran the specs by a motor builder friend local and he suggested a 260adv. duration and a 410-430 lift. I found this
http://www.jegs.com/i/JEGS-Performan...ductId=1215318
Would that be applicable or should I stay with your suggestion of using this
http://www.summitracing.com/parts/SUM-1100/
I only question this because I told him the specs of the one we were discussing and he said that it was a stock spec cam.
It sounds to me like you may be more familiar with the specs of the parts Im using. But just wanted to throw it out there and get your feedback before I purchase a second cam. Thanks for your time.

Any input?

20 years ago I rebuilt my 350 using a Competition Cam 260H. It worked great with mostly factory settings on the distributor and carburetor. The idle was not loppy but sounded crisp at idle. But like you, I wanted a choppy idle. 10 years ago I installed a Comp cam 280H, increased the compression to specs of the cam with headers. After countless hours of tuning the ignition curve and carb for a smooth operation, I find I have barely enough vacuum for my power disk brakes at idle and I am tired of keeping the RPMs up for city driving. (4spd car) Now I have decided to return to something that is close to a factory engine.
I like Jake’s recommendation but if you’re like me, sometimes you just need to forge ahead and lean from your own experiences.

Reading through all this again, to refresh myself, I don't think that 1100 cam is much warmer than the stock grind. Such a small difference might not even make a difference, if you know what I mean.

Look at this one:

http://www.summitracing.com/parts/SUM-1787/

If you want something a *little* bigger, choose this one:

http://www.summitracing.com/parts/SUM-1069/

Looks like I am going to have to return this one http://www.jegs.com/i/JEGS-Performan...ductId=1215318
And order this one http://www.summitracing.com/parts/SUM-1787/
Transmission is going to the rebuilder today. Cant wait to get back on the body.
Thank you for all the help Jake.

I like this tread. Any news?

The motor is completed and sitting on the stand in my shop. The body is atthe paint shop. Hoping to have the motor back in the next couple weeks.