Thanks George......

 

Typically you spot face the head bolt holes to keep them flat.

JIM

 

Txs Jim.

I learned something today....

 

The intake face of the head, not the face of the intake, is getting milled, same with the bolt holes, spot faced on the head not the intake.

Already have, the 406 now has a set of Dart SHP's with 197+cc's.

 

All my vette motors are fully studded and the even though the blocks are blue printed (supposedly) It is still a pita to get heads on and off because of stud to head hole clearance.

427 motown SBC

 

Gotcha...was congratulating you on doing it the right way!


Now even better...I see the 406 has some heads...but you know you could have gone bigger??

Just messin' with you....


JIM

 

Sorry, I guess I read that wrong. Yes bigger.....Lol.

Cool thing about AFR's is that here is a 180cc head that flows better than my 195cc Darts or pretty much any other 200 cc head and it's doing it with less volume. Tony Mamo knows what he's doing.

It should be a win-win for the 350. More velocity and greater flow.
Maybe I'll hit that 300 RWHP yet. That should keep me happy for a year or two.

 

Ah yes....."the dreaded year or two".
Goes well with the......."while I was at it"

My present affliction....

 

Thought I would update this thread on my AFR heads and the outcome.

It took a while as I also got the rear diff rebuilt and the ratio changed from 3.08 to 3.55.

I ended up polishing the exhaust ports and the combustion chambers on the heads and left the intake tract and ports alone on the new AFR heads. Heads angle milled to 56cc's and confirmed with cc'ing the heads when they arrived. Actually one head was 55.5 cc's but close enough. The intake valve actually protrudes below the deck surface.

Intake ports confirmed at 180 cc's as advertised vs the Dart heads that were significantly oversized when they arrived.

I also took the time to port out the performer 2101 intake manifold. I opened up all the smaller CSA's to at least 1.95 square inches. Made all the transitions in the main plenums to the port runners gradual, raised the roof and opened up the volume of the main plenums. Left the finish as a textured surface left by the burr for maximum fuel suspension and a good surface turbulence vs a laminar flow attempt.

On initial start up the engine sounded roughly the same at idle, that's where the similarities ended though.
Immediately it was apparent the engine had significantly more snap as I flicked the throttle open, instant throttle response.

On the road the engine is much louder than it was before. Now at 10.6:1 CR vs the previous 9.9 CR.
The throttle response is so quick it now is impossible to accelerate as I did before without spinning the tires. I have a new torque converter that stalls at 3000 RPM vs the previous 2600, and the engine is developing significant torque now by that RPM.
My 0 to 60 times were 6.5 to 6.7 seconds with the 3.08 and Dart heads.
Now it's difficult to get a good 0 to 60 due to wheel spin, even on grooved concrete after spinning the tires to make them sticky. But best time so far with some wheel spin and backing off the throttle is 5.45 seconds.
Keep in mind these times are at 3500 feet not sea level so are going to be slower than a sea level time. A sea level time if the tires could be made to stick may be around 4.8, 4.7 or thereabouts.
Would really like to get it on a 1/4 mile track now.

Dyno will definitely be in it's future to see the differences from the other heads.
All in all a success. The additional velocity of the smaller 180 cc intake tract is apparent with the throttle response. The intake manifold now more closely follows an ever diminishing CSA to the head for good velocity into the head as well.

 

Nice job, amazing what some airspeed, compression will do.
Wanting to go a little smaller on heads here also. Used to be heads were so crappy all you could do was try and go bigger lots of good options these days.
Next time someone says Gen 1s are no good and why not put a used LS1 in you can pound a little common sense into them.

 

Thanks cuisinartvette, I expected there to be some improvement over the Dart heads, I just didn't expect it to be so dramatic.

It's almost as big a difference as when I went from stock to the Dart heads. For sure the cam likes what I did.

 

Awesome news. Good to read all your plans came together. Myself I would be reluctant to mill brand new heads.

So I looked over your thread but not sure your motor size now or what cam you have. Just some FYI as my Camaro has severe traction problems also but I've been reading it now needs lower control arm relocation brackets to get it to squat and hook. Not sure how you would change the Corvette trailing arms for this but it reads like you are headed in that direction for better traction.

Thx for the update. Pretty cool project you completed.

 

Thanks Cardo. It's still my stock 2 bolt main 350 block, stock bore. Cam is a retro roller 270/270 219/219@.050 108 LSA with .549 lift.
I'll worry about traction when it comes time to change the tires I figure. That will be sooner now I suppose.

 

Great result, congrats!

 

Ya thanks for the update....I wish more guys would do that.

You just need some of those sticky street tires now to have some fun....

 

Me too. Usually you end up wondering how whatever they did worked out.

I can say that the AFR heads are in my opinion worth the money. Everything checked out within spec. Valve guide clearances, spring rates and valve install height, chamber, intake and exhaust volumes were all within a very small error or right on the money.
All I did was shim up the spring a bit to get more seat pressure and get the spring compressed dimension closer to coil bind while open, other than smoothing out the CNC grooves where needed.

 

TCracingCA, Read the whole thread.
The Dart heads do not flow nearly as well as the AFR heads and had damaged valve guides.
The AFR heads have appropriately sized intake runners for proper intake charge velocity.
This is an altitude build. Every bit of compression is going to matter. It went from 9.9 to 10.6 BTW.
The results speak for themselves. It's a different beast with this combo.
Carb and headers are already in place, as is cold air intake and appropriate timing adjustment and curve.

It amazes me how many people are willing to tell you what won't work but have no idea what will.

 

Stupid Iphone and probably Iphone user (me!). I thought I was at the end of the thread, so I replied , and after that loaded realized the phone hadn't loaded Page 2 yet!, because I saw different posts in front of mine, where you had bought new heads! Good move! I deleted immediately within a minute or so, but you are fast! Glad to read you are happy! Let us know when you make the next jump in compression to like 12.5:1 and I will come back in!

 

I feel your pain with the apple anything, I'm responding to this on an iPad.

Guess I just happen to be on when you responded before you could delete. I don't see your post now.
I'll probably stick with a compression in which I can run pump fuel for the time being. Although if a guy did it right 12.5 is likely doable with premium. So far I'm mixing the fuel to 88 octane with no detonation, may try lower. 9.9 cr tolerated 85 octane with no problems.