Andrew 19

Has anyone used the xm270hr or the 276 in a 383 build. Any input = THANKS R.M.

getrdunn

have used the 278 in a bbc with very good results. either one of those two would be a good choice though. be sure and look up howard cams also. they have some awesome grinds that work well with marine app. i did use the 280 magnum cam in a 350 a long time ago in a little checkmate. i worked well also. that was way back when , when reversion wasn't such a big deal.. you just had milkey oil until it got up to temp. LOL...

check out these here.
http://www.competitionproducts.com/C...partments/315/

Ryan00TJ

I ran the XM276HR in a 355ci SBC back in 07. I ran 1.6 crane Gold's on the intake and 1.5's on the exhaust. Made the cam a 226/230 .537/.511 112+2. Idled 750-800rpms neutral and could be idled down to 600rpms in gear without stalling. I think it pulled around 10* vac @ 800rpm idle. WOT for max power with my AFR heads, etc.. was 57-5800rpms. You will need longer than stock risers as I experienced reversion in the center runners of my manifolds with Imco stock length performance risers. I welded on 16" extensions to the risers to prevent the reversion.

That cam in a 383 will idle even better than it did in my 355. Very tame with a noticeable chop. It will want to revert more do to more cubic inches than in a 355. It will also run out of breath around 5000-5200rpms in a 383 vs 355.

Andrew 19

Ryan: I plan on using emi thunders w/hp (long risers) think that will solve the reversion issue?? Also will I still achieve the 450hp & 500 tq @ 5200 rpm ? Thanks again. R.

wtfo

I've had a xm270h with 1.52 ratio rocker arms in a 383 with 10:1 compression, etc... and it runs well. it will idle down to 500 or 600 rpms without dying, but it obviously does not sound stock at that rpm. it pulls hard welll past 5200 rpms, and to be frank, your heads and compression ratio are going to be what limits your horsepower potential...

I'm running imco powerflows with longer risers and have had no hints of reversion. my exhaust does come out above the rub rails.

powerplay230

andrew19 I have a comp cam xm276hr that i ran in my new 383 this yr. It was a little too much cam for my glm exhaust. I was getting a little reversion at lower rpm's so i pulled it out.This cam is for a o.e. roller block it's not the retro fit one. It has around 35hrs on it. If interested let me know i can make u a good deal

Ryan00TJ

I would call EMI and be sure with them. However, I don't see it reverting with the long EMI risers.

wtfo

I would agree wholeheartedly with this if you're using their standard length risers....

Holeinthewater

I've got a similar setup although it's not in the boat yet, I'm confident it should work nicely.

355 four bolt truck block
Manley 6" H-beam rods
Manley 10:1 flattop pistons
Brodix Track 1 aluminum heads 68cc 2.08/1.60
Compcams BBC Behive springs
Compcams Magnum roller rockers
Compcams XM-270-HR cam
Compcams roller lifters
EMI Thunder Aluminum Exhaust manifolds
EMI standard length stainless risers
Edlebrock Performer RPM intake
Edlebrock Performer 750 marine carb

Just finished assembly, it should go into my 1993 Baja 204 (old version of the 20 Outlaw) this spring! Checkout the link below of pictures I have posted on Scream and Fly

http://forums.screamandfly.com/Galle...y.php/cat/3345

Marco

dawg58

Dawg's onboard and checking things out.
I'll let you know what I think about things.