First off going to be using my truck mostly for some 4x4 and some hauling a camper. It is a 4sp truck. So have a complete engine at the machinists. The 400 crank has just been turned 10:10 ... stock heads have checked out good. Will be using a performer intake with 1406/1405 carb. Also wanting to use T.Meyer's new 9.5:1 zero deck height pistons when he gets them in.(will be contacting him in the next few days) Any input on which cam i might go with? Kinda leaning towards the 255deh. Any thoughts on this build? Or guestimated power/torque?
A few months back, danlee posted some desktop dyno results on all three of the DEH cams, the 255, 265 and 275. As I remember, as you progressed to the higher cam grind, you gained horsepower but lost torque. I came to my own conclusion that the best "middle ground" cam with good hp and torque was the 265. If you want more torque, but less hp, go with the 255. If you want more hp, but less torque go with the 275. The 265 seemed to have a better balance of hp and torque, IMO. I will see if I can find the thread. If not, maybe danlee wouldn't mind running all three cam grinds again through desktop dyno
EDIT: I found the thread, browse through this and there are some numbers that danlee ran
I put the Comp Cams 265DEH in my 79 F250's 400 a few months ago (along with a 4 barrel, Edelbrock Intake, and the headers that I already have). I went with the 265 because as 53' said it's a good compromise between the 255 and 275. I too pull a with my truck and with the 265 your power is at a little higher rpm and that seems to make it a good towing cam. It made a HUGE difference in my truck, and the fuel consumption doesn't seem much worse (if I can manage to stay out of the four barrel).
I think I like the XE cams from comp better...at least on paper. The XE256 has a bit more lift than the 255deh but is still similar duration.
A huge factor is your compression ratio. You would be cutting it way close using the 255deh and 9.5 cr and could end up having to burn 92octane. I crunched the numbers on Tim's build that was similar and the cam he used was way more aggressive than the 256 and even 265 which means the dynamic compression was lower than if he used the 265 cam- he was happy that it burned 87 octane.
My cam is special grind roller that is similar to the XE 256-262 and I will be using the kb pistons Tim had made for the aussie 2v heads that I have. My dynamic compression is higher than tim's build so we will see as far as 87 pump. I guess you are getting his special zero deck hypereutectic badgers? He will have the info you need.
For some unknown reason folks in the business do not talk about dynamic compresion which is the big cheese when it comes to cam selection.
I ordered the 265 k-kit. 400$ca. To piece it together was more, 478$ca. Probably pick up a double roller timing set tho. the pistons will be a kb zero deckheight (1.710 comp height) with a 14 cc stepped dish think i remember that right. TMeyer is having them made up (For use with stock heads) =)
My cam is on reg. backorder so probably have couple weeks to change my mind if i really wanted. Would this not be a good choice? Would be nice to run on 87 octane.
If your getting the same pistons as mine...tim's kb's with 30cc relief and the 1.710 compression height and using stock open chamber heads (78cc chamber volume)...I calculated your compression ratio to be 8.1:1- 8.3:1. That is way low! and a 265 cam will make that worse...
The 1.710 is not quite zero deck and the relief area is designed to match higher compression heads so you will lose quench.
They are made to get 9.5 or so with 60cc aussie heads....
If your compression is that low then your motor will be a big disappointment I think. I must be missing something???
If not...you really ought to be using the badger flattops and get the 9.1 compression you need. Otherwise your whizzing in the wind imo.
Last edited by roger dowty; 07-21-2006 at 01:36 AM.
no only 14cc dish. with a 14 cc dish i'm gettin a c hair over 9.5:1 think my figures are right. also the heads i'm usin were apparently shaved .020 or according to some magazine build. didnt know how to factor that in my calculations.
cool...I didn't know those were available...are you sure they are kb...sound like badger at $170. With that compression you will need the 265 as the 256 would probably have led to higher dynamic compression than you want. I obviously need to read posts a little better!!!
I started on my kids windsor build tonight and will do my 400 next. Excited to say the least.
Ok so the dynamic comp. ratio is ok with the 265 then? Did some reading and have a pretty good understanding of dynamic comp. now although could probably read it again and am still a little gray in the calculation part.