Help With New Acquisition - 250 Crossflow

rocklord

rocklord

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Just acquired a rebuilt 250 Crossflow; should receive it sometime next week. Here are the specs:
76DA Block
82 Alloy Head - unknown casting and cc
Crow Cams 14613 hydraulic - PO wanted low end torque for his E-100
New rod, main, cam bearings, oil pump, and dist. gear
Weber 34 ADM Progressive 2 BBL - rebuilt with stock intake
Stock exhaust manifold

First question, what HP should I expect with this setup?
I already have a 6-2-1 extractor, and Aussispeed 4Bbl intake, Autolite 4100 1.08 480CFM, and a Weber 32/36 for a 4.2L Jeep.
Should I replace the carb, and if so with what carb and manifold combination?

I would like to run the engine in my Mustang with minimal changes (no internal) until I can rebuild the other crossflow in my possession.

I have the following crossflow parts collected for my rebuild:
84DA casting EFI crossflow engine - complete with EFI intake
Aussiespeed 4Bbl intake
OEM 2Bbl Weber intake
AussieSpeed 6mm Phenolic manifold spacer
Set of 200 crossflow rods
ACL .040+ 200 rod pistons
Crow Cams #14892 hydraulic cam
Crow Cams # 7738-12 valve springs
Crow Cams double roller chain and adjustable gears
Aluminum roller rockers
Crane Cam Rocker Arm Guideplate Conversion Kit 52655-16
Triple DCOE intake
Autolite 4100 1.08 480 CFM carb

Would any of the above parts (double roler chain, roller rockers) benefit the 76DA engine?

Thanks for your input.
 
I'll attempt to answer your question, 1st the engine your getting should produce approx. 100-120HP at the engine.
The limiting factor is the carb and exhaust. You could fit the extractors and the Aussiespeed manifold with a 390 or 465 Holley
and gain considerably. As for the HP with that combo not sure but could gain an additional 50Hp. Will depend on the exhaust system
and tuning of the engine to maximize its potential.
As for your last question fitting the timing chain or roller rockers wont net you any more HP. the timing set may allow you to dial
the camshaft in (potentially netting a small increase) and the roller rockers may allow you to correct any rocker geometry issues, but ultimately increases
reliability. Hope this helps. :beer:
 
Thanks for the response ausxb.

I was hoping to install the Aussiespeed and 4Bbl on this engine without too much issue. The extractor is a long tube design ending in a 2-1/2" pipe (no collector flange) that helps in low end grunt. My plans for the exhaust is to run a single 2-1/2" pipe to a muffler then out with a single 2-1/2" pipe; optional 1-inlet/2-outlet muffler with a dual 2" pipe (like the Camero behind the axle muffler dual exhaust).

I spoke to the PO last night and found out the head has no markings between the 1 & 2 intake, so it is an XD-XE alloy head with the 57cc combustion chamber. With stock 22cc pistons that gives me only an 8.5 CR, ouch! So your 100-120HP rating shouldn't be far off.
 
The Exhaust system sounds like it will work very well and same for the Intake. I wouldn't be too worried about the
compression ratio as the camshaft is small and the dynamic compression will be fine. Then you are able to give it the appropriate
Ignition timing. :beer:
 
It should be an easy 200HP, i have 4 friends with crossflows pushing a minimum of 350 engine HP, one with the aussie speed 4 barrel is over 400 at engine aspirated, another one has triple webers, another 2 are triple throttle bodies, there are Facebook Crossflow pages. Your parts are similar to what they are running, its just the head, cam and R & D to do what there doing, but figure in big bucks, the Big H Cortina of Jims is a 14,000 motor and runs 11’s with a single carb. If you want a lot more power i would suggest picking one induction type, e.g. single aussie speed 4 barrel and carb, sell the surplus, and buy a Roller cam and lifters, my other mate Rob Thorpe on Facebook has a very large roller triple 50mm weber engine which will be an absolute beast when its running next weekend, a common denominator of almost all these engines i have listed and Mikes from here is Dean Tighe Roller.
 
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