ported heads and long rod engine's?

[Touge Tom]

i was researching the pros and con between short and long rod engine's. but couldn't find anything on how porting can contribute, to a long rod set up. from my understanding a long rod engine can have narrower intake runners compared to its short rod cousin. so since the use of narrow runner's why port the head?

i'm not building an engine. i just looking to understand.

[SU-WOOP]

the mean piston speed on a short rod engine is slower at bottom dead centre but faster at top dead centre due to the lever action on the crank and high rod angles wich reduces the scavenging effect and needs good port work to increase flow and completely fill the cylinder with fresh mix
a long rod engine moves slower at tdc but faster at bdc this fast movement on bdc with the correct valve overlap can draw in a fresh mix quicker without relying on port work and flow for assistance this is where narrow and tuned lenght runners work well
regardless of the runner size and the head port the inlet manifold should be match ported to reduce turbulance wich can cause lean pockets in the mix
there is benefits from both but its a matter of what the block can handle

[spetz]

Is a long & short rod engine classified by it's rod/stroke ratio?
If so, what constitute long rod and what constitutes short rod?

[Touge Tom]

a long rod engine moves slower at tdc but faster at bdc this fast movement on bdc with the correct valve overlap can draw in a fresh mix quicker without relying on port work and flow for assistance this is where narrow and tuned lenght runners work well

thank's

[SU-WOOP]

i can be real specific but geometry and numbers get confusing and lead to misconception of the whole idea
picture my rebuild - B18 short rod- stock crank stock bore -using the shortest rod i can find and the tallest pistons i can find this will increase the angle of the rod during the 360 and implies a lever anction on the crank producing good torque but increases load on the thust side of the bore and side loading but that short rod will make the piston travel slower at bdc and faster at tdc making timing more crucial (b20vtec high rod angle hi comp hi sideload on a block with no girdle and ur timing is wrong ****N_BANG)
b18 long rod stock crank stock bore shortes pistons i can by long skirt wrist pin all the way up the top near the ring lands with the longest rods i can find to keep the same comp ratio reduces rod angle sideload and that lever action resulting in low torque but its light uptop and will want to rev but it needs to breath needing good tuned intake to keep velocity but a good tune is crucial u dont want to lean out at 10k (b20 block b18 crank light pistons long rods vtec head killer cams painfully boring botom end but from 6500 to 10k all day) both can put down figures if built right power is produce by torque or revs wich is greatly affected by rod stroke ratio K series smooth torque high revs best of both worlds