Hey guys, my 396 stroker assembly will arrive this Monday. I'll be picking it up after work and will start the build-up soon after.

I'm going with a set of AFR LT4 210's seen here part no. 033-1057. These heads (correct me if I'm wrong) should flow enough to support my 475-500rwhp goal.

Question is, what cam should I go with? Emissions are no longer a concern and fuel economy... well, I'm already going with a 396 so fuel economy isn't going to be very good anyway, so that's not much of an issue either.

Just wanted to know whether or not any of you are hitting those kinds of #'s NA and what cam would you reccomend. Thanks.


Ps. Anybody reccomed a GM847 cam? What are the highest #'s people have made with this cam. Is it an option for me or no ?

 

i called comp cams for my 396 set up they made me a custom cam for a nitrous app motor im just hoping for 450rwhp on the motor and 600 on the juice...

 

You will probably want those LT4s ported or else I'm sure you won't go over 420 RWHP with an 847. To reach 475-500, you will also want a somewhat wild solid roller.

 

Really??

I've been told by numerous people that they would more than adequate to reach my goals. The spec's on the heads are as follows:



SB Chevy LT4 Basic Package Components

100% CNC Ported Combustion Chambers

100% CNC Ported Exhaust Ports

100% CNC Ported Intake Ports

3-angle Valve Job

Intake Valve, 2.080'' x .050'' long

Exhaust Valve, 1.600'' x .050'' long

1.550'' OD Roller Valve Spring, 220 lbs. on seat, .670'' maximum lift




That would only be good for 420 at the wheels? Wow. that sucks.

I wanted to go with those heads rather than the 215 or 220's because I still want the car to be relitivly streetable.

Anybody else want to chime in and give their opinion?

 

I wouldn't go by their advertised numbers. Most people just buy the castings and get them ported.

 

What cam??? A Big Custom Cam. 99% of off the shelf grinds are NOT radical to support that type of power.

 

Okay, maybe I should refrase the origional question. Here's the new one.

Anybody making 475+ HP at the wheels N/A ?? What are the spec's on the cam you're running? Thank you.

 

Ya gonna need a real healthy SR and a set of heads that flow 310+,and an intake to match.That will make you about 630FWHP everything else being correct. The LT-4's won't get you there unless you spend a ton of money on them.The LT-4 intake damn sure won't make it.
That will put you at about 504RWHP with an auto & about 550RWHP with a stick.

 

You will probably need those head ported but you could make 450+RWHP with a good SR and those heads. I think my motor can make 420+ with a some what small cam (CC306) and low CR 10.7:1 (made 414RWHP/412RWTQ w/ a miss and bad exhaust leak). The 210's flow almost exactly what my ported (Ported by More) 195's Flow. BTW AFR is back ordered abou 12 weeks so I hope you ordered them already

CFM@ 28''

.200--------.300------.400-----.500-------.550------.600------.650
I----E------I---E-----I---E-----I----E-----I----E-----I---E-----I---E
139-115---205-160---254-185--280-198--283-205---285-210--285-215

 

Isn't there a couple guys on this board pushing like 452rwhp and someone else who is around the 450ish rwhp with stock bottom ends? On a custom hydraulic roller too.

 

with cnc'd afr's and a cam comparable to the 847/LE3 cam.

 

I dont know what kind of RWH im pulling but im mid to low 11's N/A and 9.89 on a 300shot with home ported heads and a gm847

 

a shot can get you anywhere you want, as long as you have the bottom-end to support it.

 

I would talk to Phil at Ai. I thought i remember saying he was gonna test some packages to that would put out close to 500rhwp on stock short blocks. This was a while ago so he may already have them, i'm sure i saw him post about it. I would have him do my heads then select a cam to match.

 

The "race-ready" head that you linked to in your post are not 100% CNC'd runners and chambers. They are what AFR advertises as 70% CNC'd. You will need the "competition" stage heads for the full CNC. AFR's CNC work is actually pretty good if you get the full job. I do think a fully done job by the more prolific porters could get you a few more CFM.

To get to 475-500rwhp, you are going to need the full CNC "competition" heads, not the "street" or "race-ready" or whatever AFR is calling them now. In addition, you will need a custom ground solid roller cam probably in the 25x/25x duration with a healthy amount of lift. The exact specs will depend on what the rest of your setup is and what Comp Cams or Cam Motion or wherever you get the custom grind from recommends. I don't think you have any chance of hitting that power level with the GM847 and anything short of a set of raised runners or 18deg heads. A hydraulic roller is basically out the window with the setup you are talking about. Good luck.