427 SBF

Steve439 said:
Your cam is pretty big for a street cam, you might have enough overlap to get a lopey idle.

Take a look at the overlap of one of the medium size Thumpr cams (~230 intake) and see how the overlap compares to yours.
Click to expand...

Looking back at my cam recommendations again.

I have anywhere from 66* overlap (111lsa) to 86* overlap (110 lsa

The old setup was 71* overlap (110lsa)

And the current one is 76* overlap (113lsa)

The guys who I bought the shortblock from have these specs for their "635hp camshaft":

.595/.577
247/251 @ .050
110lsa
82* overlap

So then STEEB, what effect does less overlap and larger duration split have on an engine 🤣
 
Because when I Google larger split duration with less overlap the results say:

High rpm performance, smoother idle, but may negatively effect low end torque and vacuum.

Soooo
 
89 Fox 427 said:
Because when I Google larger split duration with less overlap the results say:

High rpm performance, smoother idle, but may negatively effect low end torque and vacuum.

Soooo
Click to expand...
Sound like AI google, lol.
More exhaust duration can be used to overcome a poor flowing exhaust or a very good flowing intake compared to exhaust ratio. About 75% is desired. I'm sure it used for many others reasons also, lol. Clevelands (4v) 🤮 are said to have a shitty exhaust and usually run 8-10° more ex duration. My last 408c cam had 8°, worked fine, my 1st one (358c) over 30 years ago had the same duration and lift on intake and exhaust, isky mega, lol, big no no on a Cleveland, fuckin thing worked great. This new high rpm jones cam has 6° more on exhaust, but the A3 heads do have a better ex port.
Again, my low rpm truck 414c cam has a 112° lsa and no overlap, it makes all kinds of low tq and is done by 4500rpm, using 2v Cleveland 🤮 heads.
Cams are like women, just pay for one, stick it in and hope for the best or get a used one that's already proven itself. Never never try to understand them.
 
89 Fox 427 said:
You're no fun.
Click to expand...
Incorrect response from you.

It should have been Boooooooooo.......... :)

I need to check, but I think the Thumper cams I just put in my BIL's 2006 Mustang GT have 20* more exhaust duration than the intake. I'll find the specs and edit this. It sounds nice, still has plenty of vacuum for the brakes, idles smooth at 800 in gear, lower than that I am not too happy with it, but it will idle at 600 if I want it to.
 
Mike Beck said:
Incorrect response from you.

It should have been Boooooooooo.......... :)

I need to check, but I think the Thumper cams I just put in my BIL's 2006 Mustang GT have 20* more exhaust duration than the intake. I'll find the specs and edit this. It sounds nice, still has plenty of vacuum for the brakes, idles smooth at 800 in gear, lower than that I am not too happy with it, but it will idle at 600 if I want it to.
Click to expand...
My 13 boss has lopey idle setting with the track key 😏😆
 
There was a time when I could look at a cam catalog and choose something that fits the combo I had at the time. Ever since I got into the power adder stuff, I don't even bother trying to learn, I'm fine having a cam spec'd out by people who do it every day. I've had 2 custom from Comp Cams, and the last one for the turbo I got from Bullet.

Hard to compare what somebody is using with an automatic, to what you can get away with having a stick.
 
Just to further muddy the waters, here is one of my own experiences with a cam swap. This was a long time ago, but I still remember it well. 396 BBC. TH400 with a stock converter. 4.10 gear. Old Torker (single plane/canted carb) intake. Can't remember if it was a 780 vac carb or 850 dbl pumper.

OEM 396/375hp solid lifter cam. Specs were .520" lift, 244@.050, 114 LSA. It idled great (smoothly), even with the stock torque converter. However, when I stood on it from an idle, it usually bogged.

Enter Comp Cam 286S (solid lifter). Specs were .561" lift, 236 @ .050, and 110 LSA. Again, stock converter. It did not like to idle in gear. Definite lope. But.. when I hit the throttle, it never even considered bogging. Pulled much harder in first gear. And when I changed to a little bit looser converter, the ETs dropped a bunch, and it was easier to keep it idling in gear.

Just my experience and what I have used as a way of looking at LSA specs since then. Take care. Tom Worthington
 
Tom396 said:
Just to further muddy the waters, here is one of my own experiences with a cam swap. This was a long time ago, but I still remember it well. 396 BBC. TH400 with a stock converter. 4.10 gear. Old Torker (single plane/canted carb) intake. Can't remember if it was a 780 vac carb or 850 dbl pumper.

OEM 396/375hp solid lifter cam. Specs were .520" lift, 244@.050, 114 LSA. It idled great (smoothly), even with the stock torque converter. However, when I stood on it from an idle, it usually bogged.

Enter Comp Cam 286S (solid lifter). Specs were .561" lift, 236 @ .050, and 110 LSA. Again, stock converter. It did not like to idle in gear. Definite lope. But.. when I hit the throttle, it never even considered bogging. Pulled much harder in first gear. And when I changed to a little bit looser converter, the ETs dropped a bunch, and it was easier to keep it idling in gear.

Just my experience and what I have used as a way of looking at LSA specs since then. Take care. Tom Worthington
Click to expand...

There was a guy, "SWC Duke" I think that worked as a GM engineer for years.
He would rant and rave that the modern cam's overlaps are way too much for street cars.
He was entertaining.
 
89 Fox 427 said:
Looking back at my cam recommendations again.

I have anywhere from 66* overlap (111lsa) to 86* overlap (110 lsa

The old setup was 71* overlap (110lsa)

And the current one is 76* overlap (113lsa)

The guys who I bought the shortblock from have these specs for their "635hp camshaft":

.595/.577
247/251 @ .050
110lsa
82* overlap

So then STEEB, what effect does less overlap and larger duration split have on an engine 🤣
Click to expand...

I'm still trying to find out the overlap for the Thumpr cams.
I've given up.
Not too many years ago I'd look at a cam and just click a link to see the fully filled in card.

Is that Shafiroff's cam street compatible?

You need to take it all with a grain of salt.
Remember the videos that said you couldn't hit those numbers without about .675 lift or something...
 
Steve439 said:
I'm still trying to find out the overlap for the Thumpr cams.
I've given up.
Not too many years ago I'd look at a cam and just click a link to see the fully filled in card.

Is that Shafiroff's cam street compatible?

You need to take it all with a grain of salt.
Remember the videos that said you couldn't hit those numbers without about .675 lift or something...
Click to expand...

You have to go to wallaceracing.com and find the overlap calculator and figure it out yourself. They don't list those numbers anywhere I can find.

The shafiroff cam is listed for their pump gas builds. I don't want to assume anything, but yes?
 
Can't even get the new gear on there. Old one slides on and off. Everything is oiled. Start tapping with a dead blow around the perimeter. Get fucked

20250614_082433.jpg
 
Do any companies bother to clean up or deburr their products? Getting really fed up here

20250614_081858.jpg
 
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