Looking for some advice on a stock sbc 350 build

[Greasy Harley]

...basically a duplicate of the factory 350/300hp cam.

Nothing special needed for the build, stock oil pump, stock timing set (I would NOT use any type of double roller chain set-up), stock pushrods and rocker arms.

The key to success with the SBC is tight squish...

Hey Cliff,
I'm building almost the exact same engine RN, and just installed a Melling Double roller timing set. I've used lots of them and always thought that was "the way", but TBH I never really looked into it and just took it as gosple.
What's wrong with them? drag? quality? harmonics? weight?
I'm inclined to just run it, but legitimately curious why you don't recommend them.

[Cliff Ruggles]

Right to start with a roller chain isn't nearly as strong.  They are not "constant tooth contact" so you get more spark scatter from the distributor.  There is also no tensioner to keep them from flopping around when they get loose, and they do get loose in a hurry.  It's my opinion that lacking a tensioning system allows them to really start flopping around when they get loose and accellerates the wear.

If you've ever peaked into a chain driven 4 X 4 transfer case you will NEVER see a roller chain there.  It wouldn't last to the bottom of my driveway in a 6000 lb truck on hard pavement in four wheel drive mode.

The roller chains also have multiple wear points, and many are low quality.  The only one I'd even look at for any of these engines would be the high end Cloye's or Rollmaster with the IWIS chain on it.

I've pulled down a good many engines several years after full rebuilds and you'd be surprised at how loose the roller timing sets are.  We don't get accurate feedback with this sort of thing simply due to the way these vehicle are used.  Most don't see much more than a couple of car shows every summer, couple of trips to Dairy Queen for ice cream, and maybe one or two trips to the local track to make a few passes on a Friday nigh test & tune session.

I actually tried one of the "high end" Rollmaster 9 keyway double roller sets back in 1999.  It was highly recommended to me and came with an engine "package" I bought when building the first 455 that went into my Ventura.  I was racing the car a lot back then, and lots of street driving.  Four year later it had to be replaced.  Got so loose you could just about walk it right off the gears!

I used a 3/4" wide Cloyes in the next 455 build in 2008.  In 2022 the timing cover developed a coolant leak and had to be removed.  I bought another Cloyes Morse type timing set to replace it.  When I got the timing cover off the chain was still pretty tight, with only witness marks on the gears.  Put on new gaskets and buttoned it back up and good to go for another 15 years or so......

Pictured below is one I bought off Ebay recently and the type I prefer to use.  Steel sprockets and 3/4" wide chain.  One of these will easily last the life of the engine......

[quadrajam]

Be aware that COMP makes a wide remorse link timing set part # 3200. I used one
for my latest SBC last year and it was a piece of dookie. Slack 1.5 degrees out of the box.
Checked again @ 1500 miles and was 3.5 degrees slack. Got a Cloyes double roller
from LPS and put it back together. I dont think any other company makes the 3/4 wide
chain anymore. You would have to be lucky and find one NOS from ebay or swap meet
etc. ....

QJ

[Cliff Ruggles]

They still offer the wide link belt sets for SBC and Pontiac.

Try Googling part number 3-489S, Melling or Speed Pro.

Here is an NOS 3/4" wide Pontiac set on Ebay:

https://www.ebay.com/itm/255023708000

I would never use any type of double-roller timing set in one of my engines.  Even so I would recommend anyone going that direction to get a set with USA made billet sprockets (9 keyway) and the IWIS chain........Anything less than that is bovine excrement.....IMHO....

[quadrajam]

Thats good information to know. I ended up finding a TRW wide set on ebay NOS. One day when
I get caught up I will swap it out.

QJ

[Cliff Ruggles]

Here is a pic of my favorite timing sets, with steel sprockets and heat treated gears.  Very rare these days but the very best timing sets ever made for these engines.....IMHO...

[tschmitt]

Any recommendations on what shift points to set with this combo from my first post? I'm considering modifying the governor in the th350 but I'm not for sure what the ideal rpm I should shoot for in regards to shift points with this cam/engine combo.

[Mudsport96]

Somewhere between 4500 and 5000. That is a pretty small cam on the .050 numbers. Pretty close to a stock late 70s truck cam, so no need to rev it out. Heck, I would just leave to Governor stock and see how it does.

[tschmitt]

Somewhere between 4500 and 5000. That is a pretty small cam on the .050 numbers. Pretty close to a stock late 70s truck cam, so no need to rev it out. Heck, I would just leave to Governor stock and see how it does.

Thank you for the information I appreciate it. It currently is shifting around 2500 or so 1st-2nd, 3500 2nd-3rd at WOT so I'm looking to extend both of those out quite a bit further. Very snappy and pulls great but can always try for more. I believe each governor is calibrated to the application it was initially intended for so it may have just been the factory preset for that particular vehicle, whatever this th350 came out of.

[Mudsport96]

With that info, and the info from the first post saying you have 4.10s, it sounds like you have the same issue my nova has. The calibrations for the governor is for a highway gear. So it is spinning faster and thinks that your road speed is way higher than it really is. I just manually shift the car if I am really wanting to get into the secondaries. You could try trimming or grinding the weights to see if that helps some.

[77cruiser]

You have the detent cable hooked up & adjusted?

[Mudsport96]

Are you running the 4.10s and 32 inch tires yet or still short tires?
Do you know what gear ratio the vehicle that the th350 came from had? If not I'll throw a few random things out.

If it had a 2.56 gear and you are running a 4.10 the governor is spinning roughly 60 percent faster than it would have in the original application.
Most let's say caprice and malibu cars in the 70s to 80s were cammed for economy so at WOT they would probably shift around 4200 to 4500. What is 63% of 4200..... 2700. So if the tach is relatively accurate it should shift where it is. You could try grinding some material off of the flyweights, or see if a local transmission shop can get a governor for a th350 with a higher gear.

[tschmitt]

Thanks for the replies fellas. I changed to 3.42 gears, still with 32 inch tall tires though. Kickdown cable is hooked up and adjusted correctly, passing gear works flawless. I'm going take the governor out and slowly take off some material from the inner and outer weights. From what my research shows the inner weights affect more of the 1-2 shift, outer weights more of 2-3 shift. I'll be using a gram scale to measure all of them to start with and slowly come down from there. I'm not sure what the th350 came out of but I'm sure I can get this dialed in to what I'm looking for. Just some trial and error.

[Mudsport96]

That is one way to go about it.
I just left mine as it is. And like yours at WOT it shifts at like 2500 to 2700 1-2 and 3000ish on the 2-3.
I left it like this so my daughter can drive it and not have it get away from her if she floors it.
So I just manually shift it at 5500. It makes for nice low rpm around town driving shifts.

[tschmitt]

That is one way to go about it.
I just left mine as it is. And like yours at WOT it shifts at like 2500 to 2700 1-2 and 3000ish on the 2-3.
I left it like this so my daughter can drive it and not have it get away from her if she floors it.
So I just manually shift it at 5500. It makes for nice low rpm around town driving shifts.

I can understand that. From my understanding with how the th350/th400 works is the vacuum shift modulator has more affect on the part throttle aspect (firmness and RPM range) vs the governor at WOT so it shouldn't have too much of a affect on just daily driving. Not saying it won't change it at all but from what I have gathered it will not change the part throttle shifting to say 4,000+ RPM during daily driving like it will for WOT.