I've been reading up about the SR20DET swap in the 240sx for the past couple months. I've read some item mentioning Red top and Black top SR20s. Is there any difference between these motors or is it just the color of the valve cover that their mentioning? Thanks

silvia/180sx red top = 370cc injectors, t25
silvia black top = vvt, 480cc injectors, t28, higher comp
180sx black top = 370cc injectors, t25, (stronger internals than red top)

silvia and 180sx blacktops can be differed by the vvt hump on the front of the valvecover. doesnt really matter which one you get.

So it wouldn't matter which one I would buy?

not really.

There's also the S15 SR20 with a T28 BB turbo, but since you could always upgrade to an S15 turbo, it's not really worth it unless you really want the S15's 6-speed.

So it wouldn't matter which one I would buy?

it does matter, with the money you would be spending dont jump in thinkin everything is the exact same

an s13 blacktop will MOST likely, but not gauranteed, have less miles than a s13 redtop, and will be newer since they came from later years, the redtop is from damn near the eighties, and the internals on the blacktop are slightly stronger than the redtop..

and the s14 blacktop has bigger turbo (ball bearing), as well as VVT, which is good if your lookin for a nice wide power band, it also made more power stock, and can be pushed to more power without a turbo change

So, what would be the best one to get?

s14 is the best if your not trying to make a shitload of power, b/c above like 400 the vvt is said to get in the way...

s13 blacktop is the second choice, b/c of stronger internals and newere models

s15 is best for low power/semi stock applications. redtop is best for max power, since the high port head flows better than the blacktop head.

is the high port head exclusive to red tops or do all s13 SR engines get it? does the 180sx blacktop have it?

all s13's had a high port head, s14's had a low port head

yay for FAQ http://www.automotiveforums.com/vbulletin/showthread.php?t=92927

I also believe s13 sr20det had slightly different head machining differences in the redtop and blacktop, such as the cooling fins on the front of the head for the blacktops...