engine tin differences

[mtcamper]

I asked this question on the samba only got one responce. In searching the subject found other responses and no diffinitive answer. My main question is what style of tin cools better, and will my fi from 79 2.0 fit with this tin? The long block I have was FI but before that was carbed.,,,, Here is my original post...
I recently picked up a new long block and it came with some tin. Looking at the cylinder and head covers I noticed my OG tin 79 fi 2.0 is different, as in it has dents between the cylinders not from wear but appear to be factory and the new tin I have has no dents in between the cylinders on one side, and the other a much smaller one . I'm assuming the impressions or "dents" from my 79 tin is so the fi cables and vaccum lines can run across the engine easier. So my question is if I use the other ones is there any benefit or negative affect. It seems to me the tin without the impression would have better air flow? I;m sure the new tin I have is from a carbed year so is this the difference? Opinions please.
PS: the black tin is from the 79 and the blasted tin is from 73 to 75 not sure though.
Thanks, Ryan

[ALYKAT III]

I see there are no ideas here. Maybe ask the same question on the engine thread in case there are different guys who frequent that one who are not on this thread as often ?

[ajdenette]

that is a good idea try the type 4rum unfortuantly though I have lots of bus parts I am a vanagon guy and dont know these subtle differences.

[mtcamper]

Thanks for the responses with posting advise. I have decided to use my og FI tin, the black ones. Through some other vw forums it seems this may work better for my FI and it should not have any effect on cooling . Who knows? It would be nice to experiment and test both... But I really dont feel like pulling my to swap tins.
Thanks, Ryan in MT

[fusername]

... i didn't even know there was a difference... and i call myself a T4 guy...

[subtaf]

I think you'll find that your tin (black) originally used on your factory EFI motor has the dents so the EFI runners clear the tin as it runs to each cylinder head. The tin (silver / blasted) is of an older factory carby feed type 4 motor and clearancing for EFI runners was not required. Hence no factory indentations.
Cooling effect will probably be very minimal as the air has nowhere to go apart from around the cylinders & heads etc so the same amount of air / air pressure created created by the fan is pushed though the heads and around cylinders.

[tootype2crazy]

I would agree. It seems that dents would only make the air move faster, not affect its volume. The fan produces the same amount of air either way and it has to go somewhere. I think you should be fine with the FI tin. I have the same situation and I used a combination of FI tin up top and carb tin below. That is because I got oval exhaust port heads and switched to 72-74 heat exchangers. My engine runs cool enough that I can jump out after a long highway drive on a hot day and grab the dipstick and its barely warm.