405 head guys, chime in...

[diponyou]

Well I am about to have my b21ft with a mildly ported, milled .050 405 head(BCP) up and running. At the moment it has an A-cam but hopefully a V-cam will be here shortly.

I basically just want to know what cam and what type of increase in power you got from the stock head?? is it ported? Milled?? any other mods?? How do you like it?? Regrets??

I want to make sure I am maximizing the potential of this head with the right cam/mods.

[Blue245Ti]

Right now, a stock, but refreshed 405 head with Pulsair ports plugged. Currently running a T cam, but plan to swap to a B. It's been milled .08". Since the car has only run for about 15 minutes total, no idea on how it's different from the stock 160 head that came off the B21FT four months ago. Still have a few things to do to the car before I can actually start driving it. I also have switched to a B21F intake from the stock pancake B21FT intake.

-J

[CaptainWhoosh]

Well...my b21ft and stock head are rocking an RSI stage 1 cam, just dropped it in and went, working great thus far! Im sure a properly shimmed and refreshed head wouldn't be as noisy though. Didnt really lose much bottom end running the cam at TDC and it pulls real well at 15 PSI all the way to red line.

Edit: I did have the head cleaned up and surfaced lasst time the HG went, Highly recommended!

[diponyou]

Originally Posted by CaptainWhoosh

Well...my b21ft and stock head are rocking an RSI stage 1 cam, just dropped it in and went, working great thus far! Im sure a properly shimmed and refreshed head wouldn't be as noisy though. Didnt really lose much bottom end running the cam at TDC and it pulls real well at 15 PSI all the way to red line.

Edit: I did have the head cleaned up and surfaced lasst time the HG went, Highly recommended!

So its not a 405 head then correct?

[Canuck]

I run a 405 that I modded with larger valves (38mm exhausts, stock intakes) and ported on my B23E with a Stahl header and have run an RSI NA cam and an A cam in this head. It's about like what you describing (plugged pulse air ports)...and there is NO magic for a NA engine using just a shaved head ported or otherwise. As you're boosted, you'll get more flow out of the 405 than what you've got. Pay someone to give you a nice 4 angle exhaust and intake and you'll notice a difference. Get the intake valves back cut 30 degrees and keep the seat thin. Leave more seat on the exhaust (obviously) and make sure the back of the valve is deburred. You need to make sure the exhaust is getting up and flowing off the seat, so pay attention to how the machinist does the angles. In the pictures that follow - note that I wouldn't take as much off the port wall in the exhaust away from the port. I was experimenting with this head and had the machinist hog out the area from the seat to the valve stem area. I now know that this is the wrong thing to do and you need to keep some angle here to direct the flow towards the top of the port and off to the turbo. Don't gasket match, but do clean up the casting flash on both ports.

I never regret porting heads, even if they don't turn out perfectly - then they are just learning exercises.

Photo prior to seat work.

[Canuckvolvo]

Leaving the stock B21FT intake is going to kill pretty much any benefit gained from pretty much any work/changes after said intake.

The 405 will drop compression about 0.2 on an already low 7.5:1. Shaving it will help, but going with a thinner head gasket is the best way to go- increase compression AND reduce octane requirements, yes please! 405 also flows better on the intake than 160/398, so without improving flow through the manifold(s) and exhaust, you're not getting much benefit.

[Lord_Athlon]

It's on a b21ft with lh 2.2, a 90+ and a 50 trim t3/4

[dl242gt]

I have a 405 head on my 82 B21FT. It was worked over by D&F Performance of Berlin NJ. I kept the stock valve sizes since it was going to be a street performance head. Nevertheless there was a decent flow increase with his porting and flow work. At the time of install I also installed a 90+ported exhaust manifold and put a cosworth .48 turbine housing on the stock T3 center section. These combined even with the horrid stock intake manifold made for a good overall power increase. The low rpm torque and power is just fine. Better than stock. However as the rpms go past 3k it really comes alive and makes power all the way to 6800 rpm. This is also with an enem V15 turbo cam advanced 2 degrees.

I would say overall if all I did was the head it wouldn't have been that much of a good change. But coupled with the other upgrades it really was worth it.

[diponyou]

Very good info guys, just what I was looking for.


My setup will not just be head alone, it consists of
-head(ported 405)
-cam(Acam at first, then V)
-ported 90+
-turbonetics t3/to4b
-brown tops
-3in maf
-big IC

all running on lh2.2 until I get my harness, and other random stuff for megasquirt.

And to top it off I ditched the tired, leaky b21ft that had around 240k with a low mileage b21ft(140k) that has been completely resealed. I am hoping for some good results.

[Stereophile33]

2.6l NA 11:1 compression milled 405...casting flash cleaned up with an RSI stage 3 NA cam, tuned header, b21f intake and MS1 made 175whp...NA
Jonathan

[diponyou]

Originally Posted by Stereophile33

2.6l NA 11:1 compression milled 405...casting flash cleaned up with an RSI stage 3 NA cam, tuned header, b21f intake and MS1 made 175whp...NA
Jonathan

That sounds like fun

[klr142]

Originally Posted by Stereophile33

2.6l NA 11:1 compression milled 405...casting flash cleaned up with an RSI stage 3 NA cam, tuned header, b21f intake and MS1 made 175whp...NA
Jonathan

"Stage 2" cam, you told me. I don't know that there is/was a Stage 3 yet? Do you remember the specs on it? Were you guys using a Cometic and pinto belt?

[icebrick]

91 B230f, ported polished 405 @ 11:1 cr. 4-2-1 header and K cam advanced 4 deg. ( na of course).
It runs a bit rough at idle but always starts on the first roll. I usually slink around town at 2K rpm, ( its loud),
but if I run it out past 6000 rpm between shifts, it seems fast.