Has anyone ran Ported heads w/ BTR Dual Valve Springs with the stock cam?

I am wondering if running the Ported heads with BTR springs will overpower the stock DoD lifters and pushrods.

 

I know one guy did this, gained like 10 hp without ported heads, he used to have an after market cam, but when he wanted to sell the car he put it back to stock without the dod lifters it made more 6-10whp than what ever same setup he had but i don't remember exactly

 

Checkout PRAY on the Camaro6 forum. He gained power everywhere and the car holds power better up top instead of the usual nose dive.

I believe it was more like 20whp. Katech will port your heads for $500.

 

I get the desire for ported heads, but what's the reasoning for wanting to go with going dual valve springs with a stock cam? Also, I would think that you would see better gains with ported heads if you have headers and high flow cats or no cats at all...

 

I have been seeing an average of 28rwhp for my ported heads on stock cammed motors.

 

That's very impressive, great job! I've read in multiple places that GM left a lot on the table with these heads - poorly designed and don't flow well. I wonder why?

If someone sold a set with a 5/60 powertrain warranty I would pay some good bucks. Unfortunately, this doesn't look doable.

 

why would you not slide a cam in while the engine is torn apart? you will get more from a cam with stock heads than you will from stock cam with ported heads.

 

Heads are basically a bolt on deal. $$

Cam involves pulling the engine as well as DOD delete. $$$$$

 

Heads are a bolt on affair. It takes me 8hrs on average and I charge $600. Doing the cam is an entire other animal.

Don't run duals on your stock cam. There is no need and they will only hurt. The spring pressure on duals will cause un-commanded cam retard. Your stock DOD lifters are not set up for that kind of spring pressure either. And yes, as far as I know, ALL LT1's come with DOD lifters regardless of A8 or M6/7.

I recommend headers with the heads. However. I just added my heads and E85 with a tune to a stock 17' Camaro 1LE with the entire stock exhaust and we gained about 60rw.

Here is how my heads do. This was the first set. I have made some changes now that have helped things out. I only remover 13cc's. So they go from 300cc stock to 313cc ported.

Finally got the heads finished up and ran them up to the 28" SF600 bench today. I didn't grab my best ports but the ports I did first on my bench that were still right next to the stock ports. I know these numbers are easily repeatable since all the other ports I did after this one flow a small bit better. 5 cfm at most. I did mess with the exhaust seat a little on the test runner and it bit me so the .300 number on the exhaust is down about 10cfm from the others. That won't happen again. I will rework it a little to get it back in line tonight.

I focused on the .300-.600 lift numbers for the stock cam guys. I didn't increase the cross section of the heads any in either direction. Just removed what I needed to from the inside. With a different valve job and a some more short turn work I could increase the top end flow and have the head run out to .650+ lift. Right now it crashes right at .640. It doesn't gain much at all past .600 lift though. That was the point of this head. A direct bolt on to the stock motor as a complete ported top end package with my IM/TB.

Intake Flow - 1/2" clay radius inlet

Lift.........Stock......Ported......Gain
.300........212.........226..........14
.400........270.........291..........21
.500........315.........340..........25
.550........324.........355..........31
.600.......Crash.......370........ALOT

Exhaust Flow - 2"x4" exhaust pipe

Lift.........Stock......Ported......Gain
.300........173.........182...........9
.400........206.........233..........27
.500........218.........260..........42
.600........215.........266..........51

 

Dam man those are some great numbers from just only that amount of work. I may have to get mine done for the 500.00 this winter.

Plus I do agree with you using a 650 D/spring with a stock cam a lot of people have in the head more is always better. But all these part have too are needs to work together to get the max out of the total package. AGAIN some great numbers... Robert

 

Thanks Robert. But my heads are not $500. There is someone else offering their heads with a 327cc or larger runner that don't flow near what mine do for $500. All you get with their head is the port work. No valve job, no valve grinding, no milling. Springs and what not are extra as well. I think they say their heads add 12-15rw or something like that.

Here is what my car has done so far.

Graph 1 is stock vs. bolt ons and heads vs. w/ my custom cam.



Next is bolt on and heads vs. w/ cam.



Last is the full tilt single pass.



There is still more in it but this is where we are at. Still stock bottom end in a 16' Camaro A8.

 

I wouldn't say that they are poorly designed. They are designed very well for what they were intended for. HOWEVER, the exhaust port does suck from the factory and is pretty difficult to get to flow a lot. I am still working to perfect my exhaust port. The intake port once done properly is excellent. It is actually pretty difficult to improve in the flow up to about .350" lift. I have to pull out all the stops to improve that area.

 

Great stuff. When more vette guys start doing these mods you are going to be a busy man, Brett.
It's good to see all your knowledge and hard work pay off.

 

Have always said heads help even with stock cam...

may car with Texas speed heads (flow 360 at .600) and 12.1 compression with some Bolton’s and E85 was trapping 128 in less then ideal DA...
haven’t seen any other cars come close to that with just bolt ons so the heads are working

 

In a GEN 6? I have gone 127 at 3,840lbs on 28" tall tires on a slick track in my GEN 6. I was just bolt on's and my heads, DA was around 1,100. I didn't do any milling to my heads though so I was at stock compression.

 

good times!!

This was my 15 A8 vette and It was summer time and DA was over 2000... I didn’t, go WOT out of the gate either.. probably would have been closer to 130 in better DA and WOT from the get go..
race weight was around 3400 with me in it

 

Awesome job, torque curve is flat as a pancake!

 

Okay, gotcha. Good work. The goal is 9's N/A SBE. With the winter coming I think I have a shot. We will see.

 

Thank you Sir. I am still working through some tuning restrictions that are holding me back a little bit. I will be working through some of the TQ tables in this computer to see what I can figure out.

 

Can you speak more about run .008..!
This is "bolt ons"?
Your ported heads, and what else?
Gained 111 RWHP & 88 TQ?