opinions needed

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worked out a combo with my engine builder:

- 250 xflow
- standard crank (knife edged)
- rods (shot peened, crack tested etc)
- 289 rod bolts
- wade cam (profile: 1069)
- ACL race series pistons (8cc dish)
- HF5 alloy head
- head has been ported extensively, running 1.85 inlet valves, exhaust cant remember whats in it.
- cain 4 barrel manifold
- gas research 400cfm throttle (might have to rebore it to 440cfm later on, will see performance on dyno)

plugged the exact figures I have at home into a few calculators, should be around the 10.2'ish static comp.

cam specs:
lobe lift (ex .297 / in .296)
timing advance (ex open 79, close 32. in open 38, close 72)
duration @.50 (in / ex 222)
valve lift (ex 0.514, in 0.512)
lobe seperation: 110

Info: reasonable idle, good midrange, 2500 stall

what power figures can I expect with this engine combo? opinions please?

I was going to go the 200 route, but a few people have said to stick with a strong 250.
 
well I asked wade to recommend me a cam and they recommended that.

I have heard mixed opinions about gas & cams, so I am a bit worried about it..

no one seems to know the exact answer from my experiences
 
What do GRA suggest (as in, what are their cam specs)?

I'd worry about it bleeding off compression, as described.
 
here is another cam that was recommended, custom grind:

.050 VALVE TIMING
Inlet opens: -3 BTDC Closes: 37 (duration 214)
Exhaust Opens: 46 BBDC Closes: -2 (duration 224)

advertised
Inlet opens: 30 BTDC Closes: 70 ABDC ADV (Duration: 280)
Exhaust Opens: 79 BBDC Closes: 31 ATDC ADV Duration: 290

Inlet lobe lift at TDC on the over lap:.046

Valve lift Inlet: .5074
Valve lift Exhaust: .5365
 
The custom grind looks fairly close to GRA's "Voodoo" Stage IV you were considering. Both could be a little "intensive" in a car that did any amount of running around town. I mean, you'd either need a stallie or to slip the clutch somewhat when puttering about.

Either would be a real hoot as you approached flat stick!
 
Looking also at the other grinds you PM'd me about, there's a clear trend of high advertised duration - most are 285° or more, lobe centres minimum of 110° and power starting in the mid 2Ks.

I'll upset the analytical types by raising the X-factor. Some combinations and some circumstances, work better than we think they should. The discussion Stubby led elsewhere in FordSix about crank lightening vs durability is one example. It's not divine influence, just a rebalance of contributing factors in a manner defying apparent logic.

Regardless, I can't see any reason to have a CR below 10½ or lobe centres less than 110°. You may even want to grab a few "cores" and see about regrinding them with minor differences - just to find out what it could point you at. The good bit about regrinds is you'll have less headaches with the dizzy gear. Oh, and lesser costs, too.

If you're building exhaust pressure, then a split pattern cam may be the ticket. Otherwise, it could be unnecessary.
 
"Regardless, I can't see any reason to have a CR below 10½ or lobe centres less than 110°"

Hey Addo, why you say this? My final CR is bout 9.8
Should i went for flat tops or something and when you say lobe centres less than 110 you mean 112 is less or more? im confused.
 
He's looking at LPG in a warm street capacity. IIRC, you're on PULP and running a smaller cam.

So his motor can take more squeeze. The fuel will cope with it just fine, and the cam bleeds off some compression. By "less than" 110°, I meant 109° etc. It'll give a rougher idle and debatable gain in street performance.
 
Ahh im so stupid. Didnt realise your running gas rb747.
I understand lsa's and compression with gas just havent got my head around camshafts just yet.

I think my cam is pretty 'warm' its very close to the cam rb747's first described but with less valve lift.
What makes a cam bleed off comp, how can you spot it from cam specs like these. Thanks Steve

MY CAM..........

WADE 1474c/1476c

Cam lift
IN .314
EX .314

ADVERTISED DURATION
IN 286
EX 297

DURATION @50
IN 225.5
EX 232.5

VALVE LIFT
IN .471
EX .471

PHASE/LSA
114

TIMING
EX
open 81
close 36

IN
open 29
close 77
 
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