What kind of exhaust are you running to the mufflers? I think they’d work well with some 18 inch extensions on them.
Brainstormin' 440 vs 5.9 ...
- Thread starter 318willrun
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I reckon.
FX mufflers (straight through) bolted to the collectors.
and.... I love the price. Fitting for the truck... lol
3 inch mufflers?
2.5" I believe. Same ones behind the 360 now
I still remember the 318 performance goal thread and all the naysayers. This already reminds me a whole lot of that. Probably could just rename this one “The 318 of Big Blocks.” At least you’re not starting with a 361 or 413 industrial engine…
The fun part is how this all evolved. 2 months ago, this wasn't even a thought. This thread is what captured my interest into what the stock RV engine would do. It's how I enjoy the hobby, it has to have my interest or I won't even look at the idea.
1 3/4" primary is fine for a 440.
TT5.9mag
Two atmospheres are better than one
Especially one that only makes 180hp.
Same size as is referenced in the prior motorhome dyno testing.
1 3/4" is what ya got back in the day when you ordered headers unless they were fender well.
I know, we were slow back in the day. lol
TT5.9mag
Two atmospheres are better than one
With a stock rv broomstick cam I’m not sure any size header makes a difference.
i disagree. I put headers on my van with a 318 2bbl and .399 lift. It dropped the van 2.5 tenths in the 1/8 !! Gained like 2 mph if I remember correctly???? And the van already had dual exhaust.
TT5.9mag
Two atmospheres are better than one
The specific output of that 318 is much higher than the rv440. It would be more susceptible to loosing power due to restricted exhaust. And we know how bad the 318 manifolds are. Different animal.
specific output of the 318 2bbl is more than the 440 4bbl ?? Anyways, we'll agree to disagree on the headers. You have to tune to the header. Is there anyone that believes that headers and 2.5" duals isn't worth anything over the smog manifolds and 2" single exhaust ?? I guess 40 hp on the 440
TT5.9mag
Two atmospheres are better than one
If the 318 is 235hp that’s .74 hp/cube
If the 440 is 220hp that’s .5hp/cube
So yes the 318 would have a much higher specific output. You have to think in terms of duty cycle. The rv 440 has a much higher duty cycle so they get derated to make em live.
TT5.9mag
Two atmospheres are better than one
And I’m not saying you won’t see gains from headers. I’m saying the tube size won’t make much difference on a relatively stock 440. I will disagree with 40 numbers though. You will not see that much from a header on that engine
for goodness sakes. where did those HP ratings come from LOL When did any 318 2bbl have more HP than a 440 4bbl of any year....
So lets talk "real" numbers. 318 LA in '77 had 150 HP. That is .471 horsepower per cubic inch. 440 in '77 had 195 horsepower. That is .443 per cubic inch. So, you'd have to see how much HP was gained to move the van 2.5 tenths in the 1/8. Then see what % of increase that would be. The 440 being .028 behind in HP per Cube, you could almost apply the same % of increase to it's HP. So, you'd actually get MORE of an increase on the 440 than the 318. That's why I say 40 hp without doubt. REmember, the 440 was rated with manifolds/single exhaust. My van at least had duals.
The small block buster's busting on the 440. lol
The same ones busting on Salters 9.4:1 comp 500 hp 383 pump gas build, claiming it would only run 12's in an A body. LOL
The same ones busting on Salters 9.4:1 comp 500 hp 383 pump gas build, claiming it would only run 12's in an A body. LOL
I figure weird. Or maybe I figure wrong. But when I apply my math and reasonings, I expect more from this combo than most on the list. There are some that exceeded my expectations. But it will, in my belief at this point, run better than most would think.
TT5.9mag
Two atmospheres are better than one
The numbers were used just to prove the point. And in your example the same holds true. Ultimately the theory is the same and so is my opinion on you not gaining 40hp from a header on that engine. I’d almost pay for the dyno to see it.
and you may be right, but I don't see it that way.
My local machinist is very similar, in as much that he can give you performances outputs just "looking at your combination..." Sad really...
I'm surprised that you haven't been offered some "free performance parts" from the "take offs" of all the experts...
Surely someone has a decent hydraulic cam and lifters that "didn't meet their expectations" that would likely capitalize on your exhaust and intake combination...let alone them 4.30's out back!
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