Rough running problem

[bossvette]

Will I need to also ask for hardened valve seats or are they done automatically on today's heads?

Most modern street heads will have hard seats, another option that has not been mentioned are World Products cast iron street replacement heads which can be ordered in may configurations.
you can often find rebuilt heads on E-bay for decent prices, I bought a set of small chamber (305) heads with 1.94 intakes and z-28 springs for $100 last year, they would have too much compression for a Carb car like yours, but there are many others available.
good luck
Craig sr

 

[Bob Chadwick]

Bob 1970 and earlier SB's had CR of 10:1+ so in that respect on your 77 it would actually raise it to that amount where as on a 1970 or older it would be stock CR. With that in mind I suggest the 70CC versions and the difference in performance will be negligible. The stock manifolds on your Vette are pretty good so don't write those off yet. Headers are nice but the burn plug wires instantly if they contact each other. Performer RPM stuff is nice but may cause hood clearance problems with stock hood. Performer stuff is really better for street if ya have a automatic and hiway friendly gears. Just my .02. Please keep us posted as you start modifying your Vette.Moe

So what to do, what to do? :confused

I hear you telling me if I put $2,000 into 70cc heads and a cam that there will be negligible HP improvement. And if I go with the 64cc heads, the compression will be too high and then I will have problems with pump gas.

I've got the Performer manifold already on, no increase in power by itself if you ask me, and was hoping to compliment the piece and get some additional ponies.

Pardon the sarcasm, I guess I'm even sarcastic when I pontificate, and thanks for the help.

 

[bossvette]

Bob
If you stick with Edelbrock and use the Cam/head/Intake and carb combination that works best for you the performer makes its power at a little lower RPM and is best suited for street gearing.
The performer RPM makes more power at a higher RPM and likes lower gears to keep it in its powerband.

why not go EFI? with the computer control you can bump compression and make good horsepower. I don't plan on ever going back to a carb again.

 

[Bob Chadwick]

If you stick with Edelbrock and use the Cam/head/Intake and carb combination that works best for you the performer makes its power at a little lower RPM and is best suited for street gearing.

That's exactly what I want, though I want to stick with the Q'jet as I bought a new one last year. I was hoping to get in the 300 hp range but reading these posts and the assists, I'm not sure if that is feasible with these mods.

why not go EFI? with the computer control you can bump compression and make good horsepower. I don't plan on ever going back to a carb again.

Thats a thought but I was hoping to bump it up in the next year. If I go with EFI, I'm just going to wait and get a crate motor with it all together.

 

[bossvette]

Bob
basically to get the most out of performance gains the car has to be taken as a whole. You could build a killer HP motor and have it be unusable because the trans/rear dosent allow it to reach its most efficient point.
A motor built to make gobs of torque at lower RPM will work much better in an unmodified (trans/rear/clutch or convertor) street car.
An improved exhaust system is a must and should be the first step

in my particular case I built my 383 to make power in the mid-range where I do ALL of my driving. The cam, heads,intake,and transmision were chosen for a 5000 RPM power peak it will pull to 5500 but does fall off some. I can cruise at 1200 rpm at 45 mph in 5th gear without bucking and pull away smothly from that speed without any protests from my motor, my stock l-48 would not do that (it was not in the best of shape) I always had to run 3rd at 45 mph or lower speeds


I guess what I am saying is take a good look at your driving habits and build your motor to suit them
Craig sr.
ps I will be putting it on the dyno at cruise-fest

 

[Rowdy1]

I Don't Get It..

My 62 has a 327 bored .030 over. I started out with 12.5 to 1CR pistons, aluminum heads 64cc, I'm not sure without going through all my papers what head gaskets I used. I have a solid lifter cam, a carb, an MSD ignition and I run PUMP GAS. I try to always use Sunoco 94 octane but there have been times as in Carlisle where I used as low as 92 and I have NEVER had a problem. never fouled a plug, no detonation, will idle for hours and pull 8,000 after a parade. I don't even have a timing marker on my timing chain cover, it's done by ear. I'm NOT bragging, I'm just confused every time I see a post saying anything over 9 or 9.5 CR is not streetable. I can baby the hell out of it, never go over 2,500 RPM all day, drop my lovely bride off (I'm NOT allowed to smash it w/her) and bang it to whatever RPM chip I have in it at the time.

 

[Bob Chadwick]

A motor built to make gobs of torque at lower RPM will work much better in an unmodified (trans/rear/clutch or convertor) street car.

That was exactly my plan and I thought I had it figured out until I posted it. Now I am more confused than ever.

I have the 3.08 gears with the stock auto trans and converter. I'm assuming that the converter will need to be replaced after I get some HP.

An improved exhaust system is a must and should be the first step

That was done last year.

 

[bossvette]

Bob
the performer goodies should work with a stock setup, a switch to a 700-r4 and you should have a good driver.
Rowdy
I am running Flat-tops and 64cc chambers and dont have a problem but I also run sunoco ultra 98% of the time.
do you think its the gas, Holley tech told me to stick with Sunoco perhaps they have a stake in it:L

 

[MoeJr]

Bob you misunderstood what I said. I said the difference between the Edelbrock heads at 64cc and 70cc would be negligible. Sorry I may have been unclear of that in my post. Like I said I would go with the plain performer pakcage with 70Cc heads for your car. Hope I cleared this up.

Rowdy if you are truly running 12.5:1 on pump gas then you are living the good life. I would bet your cam bleeds off alot of pressure at lower rpms and in turns helps you fight detonation. Whichever it is you obviously have it right on.

 

[Bob Chadwick]

Moe

I did misunderstand that and appreciate your clearing it up for me.

Craig,

That 700r4 is definitely in the plan.

Bob

 

[Rowdy1]

A Big Help

I also have the 6AL box by MSD which throws a multiple spark each time a cylinder fires which I'm sure makes a big difference.

 

[78SilvAnniv]

Found our problem, and it sucks...

It appears my intake valve struck my #4 piston and bent the valve and pushrod. Cam appears fine.

Have 1.94/1.50 ss valves, 67cc combustion chamber, 170cc intake and 70cc exhaust cast iron heads that will be going on as soon as we purchase new pushrods, lifters and have the manifold cleaned. Heads have Z-28 120# springs and roller-tip rockers with steel retaining locks.

Fel-Pro Blue gaskets for intake and exhaust...do we need to use any gasket stuff, or are the blue lines on these gaskets "it"?
Heidi

 

[MoeJr]

I have never used gasket sealer on head gaskets before. Are those 120# springs gonna be too much for the small cam in the crate motor? Heidi update us when you get it done as I am curious about whether you are gonna have a detonation problem with the 67CC heads. how long ya think before it is on the road again?

 

[Jack]

Making an assumption about Heidi's Goodwrench motor: it is GM P/N 10067353 or similar which came with 72cc heads, pistons with about 10cc dish that lay about 0.025" below deck: Goodwrench 10067353 yields about 8.5:1 CR. Cam lift .390" I / .410" E. .... 0.050 duration 195* I / 202* E.

http://www.sallee-chevrolet.com/ChevySmallBlockV8s/gen350.html

Using same type gaskets (about 0.039" compressed) ... 67cc heads should make about 8.9:1 CR ... 64cc heads (vortec) should make just under 9.2:1 CR. On such motor, IMO either 67cc iron or 64cc vortec iron heads will manage pump gas with no problem. The z28 springs'll work just fine ... but this may be good time for a mild cam upgrade.
JACK:gap

 

[78SilvAnniv]

... but this may be good time for a mild cam upgrade.
JACK:gap

Jaa-aaack! I'm trying to be good, but you're making it very hard to resist! :L

I spoke with Chris (69MyWay) who recommended the numbers to me and when I spoke with the owner of the speed shop and told him my driving habits and goal with this application (something to work more efficiently with what I have) that is what he advised for me and he said I'd be pleased. Chris also concurred, along with my mechanic Bro-in-law in CA (wish he was in GA).

My block is p/n 10066036 and I've been told it is a 1994, 350, 4-bolt, Goodwrench Crate, Mexico. Don't know what specs it had, I'll try to clean off it's heads and get those numbers.

I'm looking to be on the road by next weekend.
So far, Kenny has mildly enjoyed the wrenching and I don't want to push him over the edge into resentment, so I'm being patient.
Well, trying to be patient!
Heidi

 

[Jack]

Jaa-aaack! I'm trying to be good, but you're making it very hard to resist! :L Heidi

We know you're good ... but ... You can get a mild cam that'll work real well with your new heads & springs for no more than $50-$60. (i.e. SpeedPro P/N CS1151R lift .420I/.443E 050 dur 204*I/214*E w/ 110* lobe center ... readily available ... probably locally ... BTW, same cam by Clevite is P/N 229-2201). You've already got a buncha stuff off the motor ... pull the rad (clean&flush) ... pull the fuel pump, water pump, balancer & timing cover/set ... cam'll come right out. Good chance the goodwrench has that crappy plastic-jacketed cam gear in it ... toss it ... new timing set for under $20.
JACK:gap

 

[78SilvAnniv]

Kenny understands that now is the time to make changes, but this will depend on exactly how much he wants to wrench and on our budget. These heads are basically my entire x-mas, and I'm not really complaining. The remainder of $ we have needs to be used to build the barn/shop, and that must take priority because if we spend the $ on goodies for my 78 we won't have the funds for the building.
Our local mechanic friend is pushing us to get a cam and double roller timing chain, too.
Kenny is coming home at lunch today to leave me his truck so I can take the manifold to the machine shop for cleaning, and I'll bring all this (cam/timing chain) up before I go to pick up the lifters and pushrods.

 

[78SilvAnniv]

Project on hold for a bit...

Kenny took a fall and broke a rib. (ouch!)

I've discussed with Kenny, if we get someone to lift the other head and manifold into place, I can turn the torque-wrench under Kenny's supervision.
So, it may take a little longer and I'll wind up with grease under my nails but I can have pride in saying "I did that!"
Heidi

Here's a pic of the #4 intake/exhaust valve I bent.

 

[Jack]

Re: Project on hold for a bit...

Kenny took a fall and broke a rib. (ouch!)

Sorry we're not closer ... I'd run over & help y'all. Yep, it's bent. Did y'all ascertain cause? ... if valve stuck in guide .. or if lifter pumped up ... or?
JACK:gap

 

[78SilvAnniv]

We think it jumped time when I romped on it.

I guess everything was in the right place at the wrong time.
I am guessing that when I floored the pedal the intake valve hung open just a little long and got slapped by the piston, which bent the valve and pushrod.
Kenny said the lifters all looked fine and except for the bent one, the pushrods looked great.

A co-worker of Kennys commented that he had a jeep that exhibited the same symptoms as mine after he stomped it and when he took it apart he found that it had jumped teeth. We will pull the front off the motor and see what the timing stuff looks like. I have a double roller timing chain w/ new gears ready to go in.

I wish you lived closer too, Jack. Kenny is in a lot of pain and taking hydrocodone, when he is awake he seeks pity/sympathy and moans and groans a lot. I notice he complained more after the x-ray confirmed the rib was broken. Is this normal for men?
I really want my car back, but I can't ask Kenny to overexert himself because of his broken rib. I know he isn't faking it, it really does hurt him.
Heidi