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Ofna picco .26 and ofna jl .28 maxx

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No doubt a side pipe will flow better with any engine, I agree....
However, since the exhaust port is so small on the Piccos, I doubt a side pipe will matter much vs a rear setup. All that power is squeezing out of a small opening and into a larger exhaust, regardless of what BB exhaust you have. The difference would be all in the pipe and nothing to do with the manifold.
 
Couple of points here for technical correctness: 1st - The effective pipe length between the cylinder exhaust port and the engine's exhaust port leading to the manifold is insignificant vs. the total effective pipe length of both the BB manifold and expansion chamber, when talking about a mid block mill (e.g., quasi direct drop ins to a REVO) such as the JL .28 MAX and Picco .26. This is technical fact. As long as you have a SB/BB exhaust port machined adapter, then effectively the engine's flue is porting direct to the BB manifold (just slightly different - albeit w/ some loss ...than a BB exhaust port would do). Power is not 'squeezing' out of the exhaust - not sure what you mean by this. No power generated in the exhaust, the thermodynamic cycle is affected by the exhaust, but not made there of course. 2nd - The manifold has a significant impact on head loss (the wasteful pressure drop) associated w/ the exhaust system. The manifold (e.g., elbows/bends) is technically referred to as a "Minor Loss" (The correct mechanical engineering fluid dynamic term). "Minor" losses are not actually 'minor' they are significant in terms of head loss across the exhaust system's control boundary when analyzing BB rear vs. side mounted pipes. The bends / change in directions associated with rear mounted pipe manifolds yields higher head loss (again, unless there is a new rear exhaust manifold on the market that I'm not aware of) in excess of side mounted BB pipe with a smooth, large radius continuous bend going direct from exhaust outlet to the expansion chamber complex (where the real benefits come into play regarding pressure wave generation for both sucking out residual exhaust gas from engine cylinder and pushing back any fresh air/fuel/oil charge that has short circuited the engine cyclinder). I'll conclude simply stating a side mounted pipe would yield more benefits in terms of getting the most power out of a mill (holding all other variables constant) vs. a rear mounted pipe. If the aformentioned is technically incorrect in any way, then advise ... I'm always trying to learn more about these things.
 
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Put a real .28 next to a Picco max .28 and you'll see how much the small, YES IT'S SMALL, exhaust port restricts the Picco mid block engines. A real .21 big block will run circles around the the .26 and the .28, I've seen it through my own personal experience......not in something I read.
 
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Oh, by the way - in line w/ my earlier rational on the Small Block to Big Block Adapter & associated engine performance re exhaust flow behavior into & around the big block manifold via the big block side exhaust. As I suspected based on sound engineering principles - I've confirmed via practical testing over the last several weeks, that the big block manifold to small block exhaust port adapter has negligle impact on performance (e.g., JL .28 MAX just sees an big block exhaust/manifold).

I recently broke in my new truggy loaded up w/ a Novarossi Roma .25 with a Novarossi super hard expansion chamber and short manifold... Don't believe anyone will debate that this mill is one of the finest out there - almost too much for a truggy.

I can say, comparing engine performance of my REVO with the JL .28 MAX with my truggy setup, I'll say that the revo has an extreme amount of power - nearly uncontrollable with a final gear ratio of 12.72 compared to my truggy w/ a final gear ratio of 11.91. I AM NOT SAYING THAT THE REVO IS BETTER - THE REVO LACKS STABILITY, TURNING, ETC., but will say that the Revo is a blast to drive w/ my setup.

Just adding a bit more factual data to back up what I was saying in the thread earlier - side mounted big block pipe with a smooth curved manifold is undeniable from a performance perspective, especially with the small block to big block machined adapter to connect the big block exhaust manifold to the small block engine exhaust port.
 

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