Open chat thread for Buick 350 Camshafts

Gary,can you redo the dyno that Andy asked for with 2.00" intake valves and 1.60" ex. valves with 295 max int. cfm @ .550" lift and 175 cfm max ex. cfm with 3.875" bore and a 4.00" stroke? Thanks.


Derek

 

Gary

I believe what you are seeing here is the result of too much intake duration and not enough exhaust for the head flow and engine displacement.
Try dropping the intake duration to 228* and upping the exhaust to 236* on a 110 LSA and see what happens.

I'm looking at a Jones cam with 228*/236* .528"/.534" 110 LSA, advertised duration 284*/292*

Paul

 

I came up with a cam not too dissimilar to that actually, Paul. I took the TA 310 cam and widened it up a bit (lowered int duration and increased exh duration). I haven't put that cam in the simulator yet, but it looks similar to what you're suggesting.

Actually, I think it's almost exactly like it...I moved it 4* in either direction if I remember correctly, which is what that cam is. I think I used a different LSA though and advertised durations. Let me check real quick.

Edit: Here's the cam out of my list...I made it some time back and never decided on a lift:

GF 228-36H-350

Suggested lifts for flat tappet/single 'Stage1' springs:

.443/.449 @ 1.55 lobe .286/.290 (wear factor: best; power factor: fair)
.459/.463 @ 1.55 lobe .296/.299 (wear factor: good; power factor: good)
.474/.477 @ 1.55 lobe .306/.308 (wear factor: fair; power factor: best)

Suggested lifts for roller with single 'Stage1' springs and stock rockers:

.474/.477 @ 1.55 lobe .306/.308
.490/.490 @ 1.55 lobe .316/.316

Suggested lifts for roller with dual springs and roller rockers (check piston to valve clearance):

.506/.506 @ 1.60 lobe .316/.316
.522/.538 @ 1.60 lobe .326/.336
.554/.570 @ 1.60 lobe .346/.356
.586/.602 @ 1.60 lobe .366/.376
...or whatever variant tickles your fancy. More lift on intake than exhaust, straight pattern, etc.

"For best results, match valve lift to head flow @ lift"


284/290 @.006 56/54 lobe intensity

IVO is 33.0 BTDC ( - indicates ATDC)
IVC is 71.0 ABDC
EVO is 78.0 BBDC
EVC is 32.0 ATDC ( - indicates BTDC)
Overlap is 65

228/236 @.050 109/113 I/E 111 LSA
2*A

IVO is 5.0 BTDC ( - indicates ATDC)
IVC is 43.0 ABDC
EVO is 51.0 BBDC
EVC is 5.0 ATDC ( - indicates BTDC)
Overlap is 10

Power Range (Shift Point): 2700-5500 (6000-6200) "2700-6100"

Static compression ratio of 10.56:1.
Effective stroke is 2.82 inches.
Your dynamic compression ratio is 8.00:1 .
Your dynamic cranking pressure is 158.97 PSI.

Wow, that's eerily close! Check that out! I swear I never seen that cam you suggested before. They're almost verbatim.

Edit2: Here's a couple screenshots of the .006 and .050 graphs using Andy's engine as before, with a dual plane and 800 CFM carb, only with my cam listed above, which is almost exact to the one Paul suggests:



The numbers are a bit higher, plus it's not using optimal compression, since I left it the same. Comp should be a bit higher.

Gary

---------- Post added at 02:28 AM ---------- Previous post was at 02:28 AM ----------

Yeah hang on Derek, I'll hook ya up in a minute.

Edit: now I'm gonna try Derek's suggestion using that last cam with corrected compression.

Gary

 

Ok Derek, here it is:



That's using my cam as above (with .550/.550 lift), 10.5:1 comp and the heads, bore/stroke to your specs, single plane intake, and 1000 CFM carb. All else is the same.

Comes to 494 HP @6000 RPM and 468 ft. lbs. @5000.

Has a nice curve, and Hp trails off slightly all the way to 6500 RPM.

I'd say the heads and intake were a bit of a restriction on that cam! lol


Gary

 

Even though no such intake exists, it has an option for using it as one of the parts. This latest graph is a good indication of what the Buick 350's potential can look like with the upcoming aluminum heads and single plane intake--that 450 HP and 450 ft. lbs. isn't an unrealistic goal for an unstroked, moderately bored, moderately cammed engine.

Imagine fuel injection on it and the cam could be a bit milder, a smooth idling 400 HP 450 ft. lb. 350 wouldn't be difficult to achieve at all.

Gary

 

Looks good,thanks Gary. Was that a roller cam or a flat tappit you whipped up?


Derek

 

Roller, but there doesn't seem to be any difference the simulation shows when using either/or in terms of power gains.

The simulator doesn't take into account for details like that I guess, which means the numbers are probably lower than what you'd see in actuality.

Still, it gives a decent general idea of what to expect.


Gary

 

I see that cam that's similar to Paul's has hi torque much longer Than the 310 cam. I see on that simulator the Buick 350s like big headers too. Would be cool to see a 350 break into 500 lbs of torque below 4000 rpm

 

That's one of my cams.

It depends.

Like this?



504 ft. lbs. from 2000-3000 RPM and 356 HP @ 4500 RPM.

Uses the same engine Derek suggested with the bore/stroke, head design, but using my torque cam in roller version with .650/.650 lift, small tube headers, and 1000 CFM carb.


Gary

 

nice Gary. so close to the "factory" spec of a stage1 455 of 360hp/510lbs with everything below 5000 rpm. Rename that one GF350 stage 1 . I know if you tweak those numbers some you can get in the range of 490/490.
try this 10 to 1, 800 cfm carb dual plane, small headers with mufflers -375 cid
intake lift 468
exht lift 489
ivo 7.5 btdc
ivc 43 abdc
evo 53 bbdc
evc 7.0 atdc
cam spec @ .050 roller
this engine would be awesome it it was real

 

Just for clarification, here is a screenshot of a Buick 350 with similar specs to the engine Jim Weise built, and the numbers aren't off by much (in fact, they're almost verbatim, even @RPM).




Gary

 

Here it is. I assumed a .006 number conducive to performance suitable for your .050 numbers.



Shows 388 HP @5500 RPM, 413 ft. lbs. @4500 RPM.

(A cam of this caliber would benefit more from the larger headers and carb)


Gary

 

For example, here it is again with large headers, 1000 CFM carb, and bumped lift on the roller cam to .650/.650:




HP and TQ are now 429@5500 and 452@4500 respectively.

Gary

 

I'm going to have to recheck my numbers. It was a tweaked version of a cam file that came with the software and it made 489 lbs at 2500 And 491 at 6000 . Maybe I'm doing some trying wrong. Raising lift of that one Made the curve erratic around 525. I tried to post it but I guess I have not figured that out yet. But it had a close to flat torque line starting at 450@2000 then stayed up around 490 to 4500 then dropped to 350 at peak hp

 

Here is another simulated engine with a 212 cam:

http://www.tworock.com/mjd/buick/350/ta-212.jpg

---------- Post added at 05:57 PM ---------- Previous post was at 05:46 PM ----------

Try this roller cam that TA Custom made:

This cam is going in a race car Regal.

 

Prime example:

The next two screenshots are with the TA 212 cam, the first one is mildly cleaned up heads with stock valves, 750 carb, stock intake and small headers.

The second one is the same TA 212 cam, same compression (10:1), but with the engine bored and stroked, hogged out heads with huge valves, using a single plane intake, 1000 CFM carb, and large headers. Check out the differences...




Gary

 

Here's that roller cam Sean, used in place of the TA 212 in that last screenshot with the same mods.





Gary

 

Good stuff Gary,thanks for taking the time to do all of this!:TU:




Derek

 

Thanks Gary, great work!!

A perfect example of how a roller cam can give both good low rpm torque and good HP. I have always said that with the iron heads ported out there really is not much power to be had over 6000 RPM unless using a power adder.

Many people including myself are more interested in the numbers and specs when they can see the dyno graphs... If you have time I will get you to do a "camshafts for dummies" summary for my book! You could summarize the learnings from what we know so far and it might help people understand why I am careful to suggest massive cams in their 350s.