Thinking about a new Cam

[mattawajeep]

So, I've got the SBC pulled out of the Gladiator, mostly cleaned up, and almost ready for spray paint.

I already plan on changing out the majority of the gaskets, and as such I'm thinking that swapping in a better cam as suggested in the Towing Engine thread is probably not a bad idea. Been doing a bit of research and I don't think it'll be that hard.

Playing with an old Dyno Program and I'd like someone who knows what all this stuff means to take a look at what I've got and see if it makes sense.


Here's some basic Info I have on the engine:

3932441 Heads

Likely 1.940" - 1.5" Valves - 2.02"-1.6" Possible

3970010 Block

V1007TKK Engine Code

1978 350 165 HP 4 Barrel for C20-3500 - Probably a 4-Bolt Main Block

Don't know what the pistons are, probably need to pull the heads but I'm assuming it's standard and compression is probably 8.00 to 1












I'm looking at this cam:

http://www.summitracing.com/parts/sum-k ... /chevrolet

It's cheap, only $99 bucks with free shipping, seems like a clone of some of the edelbrock performer cams and from what I can find it sounds like it's made by Comp Cams.



Here's the part I'm not sure I got right, some of the cam info is auto generated, and I don't know what all the numbers mean. I was able to find airflow files for my heads, plugged the long block and exhaust guestimates, and inputted the cam info.







Looks better than I was expecting. Torque curve is really flat, and high all throughout the RPM range I'm expecting to use.

Does it look too optimistic, or am I at least close to the target?

Can anyone think of a better cam that's not $$$$.

Think my stock springs will handle this without exploding?

[Lurch]

I would have the heads checked out by a machine shop. Also have them check the springs. Never a bad idea to do better valve springs.
Does the cam come with lifters? If not you will need em. Also replace the timing chain with a double roller while your in there. May also want to consider a new oil pump and take a peek at the rod and main bearings while you have the pan off.

[mattawajeep]

I would have the heads checked out by a machine shop. Also have them check the springs. Never a bad idea to do better valve springs.
Does the cam come with lifters? If not you will need em. Also replace the timing chain with a double roller while your in there. May also want to consider a new oil pump and take a peek at the rod and main bearings while you have the pan off.

Cam kit comes with lifters and assembly lube. Better timing chain, and double checking the bearing is probably a good idea, should be super easy on the stand. I'll do some looking at oil pumps.

Any suggestions on a machine shop to check out the heads and an idea of what it might cost to have them check them out?

[iaccocca]

On the heads, I can recommend Poynor's behind Baxter's in Kennewick on Columbia Ave. I'd call ahead to see if he can fit you in on a decent timeline, he does have a pretty good backlog. Oh, and you will have to bring cash. No idea what he will charge, but he has been fair to me.

[White trash]

That's about the specs on tue cam I always choose for a towing type application so it'll work fine.

Definitely go with a dual roller chain it will far out live the factory piece.

I can't recommend k&u in Sunnyside enough. They have been the go to machine shop for my family's auto repair shop for over 20 years. If you go there talk to Brian (he's the head machinist) and tell him kay mac sent you.

[mattawajeep]

Cool guys, thanks. I think I'll check out K&U, used Poynor's for a flywheel, might check out the other place this time.

Got the cam, and double roller chain ordered along with some odds and ends. Hopefully I can try and get stuff installed next week when it get's in.

If I can find something that will work well as an engine cover I might pull the heads tonight and take a look at the valves and pistons and see what's going on.

ETA:

Might want to see if I can get the air conditioning and stuff bolted up to my engine before I mess with the heads.

[mattawajeep]

Think I might have some issues getting stuff to bolt up, I think there's a couple bolt holes on the Pass side head that I don't have. Might have to source some different brackets to bolt up the AC and other stuff.

Anyway, pulled one head this evening and then the wind came up. Made room and moved stuff into the garage. Might remove the other side later tonight.

Water passages are pretty danged ugly. Everything else isn't all that bad.



Think the Tefba filter is coming out of the mustang and getting moved to this thing.




Pistons tops look about like I expected.



Cylinder walls seem to be in really good shape. Looks like dished pistons.




And the bad news, one of the exhaust valves seems to be sunk in a bit further than the others. I'm assuming that means it's wearing out.

Blurry pic of what three of them look like.



Sunk in valve:





So, what do you all think? Is a sunk valve going to force me to have the whole head rebuilt? I don't know what questions to ask the machine shop.

[White trash]

Cylinders look good since there is still cross hatching on the walls. A standard valve job will fix the heads. No reason to spend a pile of money on them for your usage. But if you're needing the accessory holes in the heads anyway just grab a set of later model "fast burn" heads and slap them on.

[mattawajeep]

Cylinders look good since there is still cross hatching on the walls. A standard valve job will fix the heads. No reason to spend a pile of money on them for your usage. But if you're needing the accessory holes in the heads anyway just grab a set of later model "fast burn" heads and slap them on.

Looked up fast burn heads. Sounds like that's a vortec thing and takes a different intake, or did you mean something else?

I'm wondering if just buying a different set of iron heads might be cheaper than a valve job. Guess I'll have to call the machine shop tomorrow and see what their prices are.



These look like they have the holes I need, and all the ports look the same. The combustion chamber volume is slightly less and it has the bigger valves. Wonder if they would hit my pistons.

http://www.summitracing.com/parts/sum-152123/overview/

[mattawajeep]

Or aluminum....

http://www.speedwaymotors.com/Flo-Tek-1 ... 25118.html

Probably actually Chinese lead.

[Lurch]

Couple if not all those valves will need replaced. Get an estimate before they do the job. May be cheaper to find a set already done.

[White trash]

The intake pattern is indeed slightly different but it's just the center bolts and a rat tail file will fix the issue.

It's too bad I didn't keep the heads that came with my latest Toyota. In the bed was a cracked block for mock up with a pair of nice clean heads. They are on their way to china by now no doubt. I did think of you though and I kept the complete tbi and all the accessory brackets off the front of the engine along with the a/c compressor.

[mattawajeep]

The intake pattern is indeed slightly different but it's just the center bolts and a rat tail file will fix the issue.

It's too bad I didn't keep the heads that came with my latest Toyota. In the bed was a cracked block for mock up with a pair of nice clean heads. They are on their way to china by now no doubt. I did think of you though and I kept the complete tbi and all the accessory brackets off the front of the engine along with the a/c compressor.

Almost finished re-building the Quadrajet from the chevy parts truck, but TBI is probably a better way to go.

Meh, thought I was only going to be spending money for gaskets and a cheapo cam shaft. Wasn't expecting valve problems from the way the engine was running. Oh well, better to spend money now, than blow up on the way to the mountains. Wonder how much life is left in those valves.

How much you want for the TBI? Might be interested in the A/C compressor and brackets too, especially if they're different than the setup I have on the suburban. Might make finding cheap heads with the right holes easier.

[White trash]

I'm easy so I'd take $100 for the whole tbi setup including harness, distributor, intake etc. Looks to be complete other than fuel pump. Buy that and I'll toss in the rest for free.

[mattawajeep]

I'm easy so I'd take $100 for the whole tbi setup including harness, distributor, intake etc. Looks to be complete other than fuel pump. Buy that and I'll toss in the rest for free.

Can't say no to that. If you'll be around early next week I'll make a trip into town, stop at the machine shop, the sandblasting place, and pick up the parts from you.


Pulled the other head. This one also has a slightly sunk valve on cylinder #3. Paid more attention to the pistons and it looks like there's a 30 stamped on all of them.

Everything I can see on the cylinder walls looks good again. I'll have to rotate the crank and check everything out.







Is this more redneck or Martha Stewart?

[Wrench]

I actually have a set of Vortec (fast burn) heads. They have less than 10k miles since the valve seats were touched up at the machine shop. They will need valve springs, but they are otherwise ready to go. PP price: $150

Your pistons are OEM 0.030" over. With those pistons, stock head gasket, and the fast burn heads, the CR will be closer to 9.5:1, but not high enough to cause pinging issues.

You will find FAR more power with the Vortec heads than you ever will by increasing the valve size. The Vortec ports are a MUCH better design, and that is where the power is at.

[Lurch]

Those would be the heads I would run. Good price too.

[mattawajeep]

I actually have a set of Vortec (fast burn) heads. They have less than 10k miles since the valve seats were touched up at the machine shop. They will need valve springs, but they are otherwise ready to go. PP price: $150

Your pistons are OEM 0.030" over. With those pistons, stock head gasket, and the fast burn heads, the CR will be closer to 9.5:1, but not high enough to cause pinging issues.

You will find FAR more power with the Vortec heads than you ever will by increasing the valve size. The Vortec ports are a MUCH better design, and that is where the power is at.

That sounds like a much better option than getting my old 60's heads reworked. I'll take em.

So I should likely be fine with 87 octane? Any suggestions on what springs/rockers I'll need to run?

ETA: Dumb question, will the cam I already ordered work with these? Or are they setup for a roller cam. I have a lot of reading to do.

[mattawajeep]

So, got a chance to do a bit of reading and I think the heads will work with a flat tappet cam. I'll just need to find some springs with a seat pressure ~100 or lower.

Looked at a compression calculator. Compression should be around 9.18 to 1 with the gaskets I have. So I'm not worried about pinging at all with cheap gas.

Just one other question, what kind of exhaust ports does it have? Looks like most I can find online have D ports, which will not work with the headers I have. Which could end up making things more expensive in the end.

[mattawajeep]

Answering some more of my own questions. Good news, looks like the round headers will match up if you use fancy D port gaskets, they leak otherwise. Was going to use expensive gaskets anyway.


Updated the dyno program with more correct specs and adjusted for the fast burn heads. Scoured the net for flow specs, found quite a few references and they all seem pretty optimistic. Who knows, maybe they're that good.









If this is accurate, it's pretty darn good. 400 ft/lbs of torque should pull pretty well.

[Wrench]

You will need to find valve springs that are designed to fit the Vortec heads. The Vortecs have a slightly larger base under the seal, and standard SBC stock springs will only fit when the spring dampers are removed. I would advise a good behive style spring, which will eliminate the need for the dampers (they have a natural resistance to the harmonics that often cause valve float).

You must either use the included stock self-aligning rockers, or buy ones that are self-aligning. The Vortec heads do not have pushrod alignment built into them like standard SBC heads.

The difference in roller vs flat tappet cam has no effect on the heads. I ran these on an older flat tappet lower end myself.

You may want to think about getting an intake for these, though. I have never checked to see how well a non-Vortec intake lines up with these ports. And stay far, far away from the "air gap" intakes. They work well in a hot climate, but are horrible in the cold. These heads already have the exhaust crossover blocked off, and if you eliminate any more heat from the intake air, you will have to run the carburetion pretty rich to get it to run well (lack of fuel atomization = very poor fuel economy). I think the prime intake to use with these heads would be the Performer RPM intakes, non-air-gap. If I remember right, the Performer RPM and Air Gap intakes actually have similar ports, if not identical.

BTW, mine have the center bolt covers included. Also, they probably flow a tad better than what you posted, the ports were very mildly cleaned up (casting flaws removed and valve guides trimmed, aka "pocket ported"). Not sure, though, as the ones you listed are using 2.0 valves. These have the stock 1.94" / 1.5". The flow is really in the port, though, not the valve size.

The exhaust ports are not D shaped. They are standard like all the other SBC types. I think you are getting the SBC Vortecs mixed up with the newer-gen Vortecs. Those are a completely different heads.

[mattawajeep]

Yeah, it was a bit confusing searching the web. It seems that GM came out with a set of aftermarket iron heads called Fast Burn with the oddball 2.0 - 1.55 valve size, and D shaped heads. Not to mention the aluminum versions. It was hard trying to get the right info with all the different heads called fast burn.

I assume that what you have are vortec heads from a stock GM engine, nicknamed fast burn? Got a casting number handy or do you know what year, make, and model, they came out of? That'l help me find springs and the right specs to plug into the dyno.

I think you're right on the intake, a non vortec intake can be made to bolt up, but the ports will be off. I need to find a newer dyno program so I can test out different intakes. I think an Edelbrock Performer, or one of it's clones is probably best on the low end with TBI.

I think I'm going to make it into town Tuesday evening next week if you and Ryan are going to be around.

[White trash]

If I'm not around someone will be. Everything is loaded up in totes already so it'll be simple to deal with.

[mattawajeep]

If I'm not around someone will be. Everything is loaded up in totes already so it'll be simple to deal with.

I think you've moved twice since I've last been by your house. Want to PM me your address? Or you can text me. 509 929 Zero One Six Five

[White trash]

3 times actually.


I'll pm you.