408 W2 head combo - suggested upgrades

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evil66

evil66

evil66
Joined
Apr 20, 2010
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Location
Australia
Hi everyone, i have a 408 stroker in a 69 Barracuda fastback here in Australia and i am looking at stepping it up a bit without totally changing everything,here are some rough specs:

10.5:1 compression,forged pistons,
Forged crank,h beam rods.
248@50 solid flat tappet cam (comp magnum) with around 540 net lift with 1.6:1 rockers.
Mopar w2 single plane manifold.
MSD distributor,6AL ignition.
750 HP holley double pumper.
TTI step headers 1 5/8" to 1 3/4"
Dual 3" exhaust
W2 econo heads,2.02 inlet valves, no port work,valve job only. 252cfm@500 lift,270@600.

Car runs 115.5mph consistently over the quarter mile and is very streetable but i think i have left a lot on the table, especially with no port work, minimal lift for a W2 head and smallish ports for 408 cubes.

Looking for any suggestions for a couple of upgrades that will wake it up a bit.
 
Mild port work to start... W2 heads have lots of room for improving,there...
Rear gear, rear tire height, transmissions(converter stall,stick?.....), what you are willing to go to,& how fat to get it... On, what you currently have.....: port the heads,get a good quick action flat tappet solid ,to match the current combination. Unless ,you want to re -engineer the whole drive train...JMHO....
 
727 auto,3000rpm stall and currently has 3.9 gears with i think a 26" rear tyre. I am willing to change a few things but didnt want to re-engineer the whole combo if i can avoid it as i have another barracuda to build.
 
The port work is the next step here but as usual, one modification usually needs to be done in tandem with others to fully take advantage. I would think port work (and gasket matching the intake/heads), carb upgrade, cam change & convertor would do it. Just think, you can use the old carb, conv (& maybe the cam?) in the next project. GL.
 
Cam change with more lift. Same/similar duration. (Avoids a converter change) May require the guides height to be addressed as well as spring fitting.
Head porting.
 
rumblefish360 said:
Cam change with more lift. Same/similar duration. (Avoids a converter change) May require the guides height to be addressed as well as spring fitting.
Head porting.
Click to expand...


Rumble is on this like a two dolla *****.

You are .100 SHORT on lift.

Get a 2.05 intake valve and use a 38* top cut. Unshrouding the intake valves. Use a 45* seat, with a 60 and then 70-75* cut and blend it into the bowl.

Keep the 1.60 exhaust and do a radius valve job on the exhaust with the same 38* top cut. Blend the bowl into the valve job.

After that, you can still make more power but it's more work.


You are WAY down on lift, even if you didn't change anything else.
 
BTW, you can make a good bit of power if you spend some time grinding in the intake manifold.

I'd port the intake long before I bought a different one that stills needs port work.
 
YR! Thanks LOL!

I didn't think of the 2.08 valve. Why, I don't know. That should have been the no brain-er!

I like the Indy intake manifold idea for later. When he runs out of the M1's ability. It's a really kick *** intake. Though I don't know much about it myself and what it would take to make it work. Below is a square port Indy I traded for an oval port Indy for. I was going to use it with the W5 heads.

A member was looking for one but decided he couldn't trust me. I just put it back on the shelf today.
IMG_0529.JPG
 
Definitely recommend port work first and foremost. Then consider cam upgrade and a good converter.
 
Thanks for all the suggestions, i was thinking cam and port work,when i bought the cam a long time ago it was going to be for a set of j heads,which changed to a set of W2s. Even when i flowed the heads i knew it didn't have enough lift to make use of them. I do have a friend who ports heads and he has suggested a 2.08 inlet valve and port job or if going further converting them to a rectangular port.
I would like to the cam duration similar but increase the lift but thought this might be risky if staying flat tappet solid and the possibility of chewing out an agressive profile.
I do have a set of mrl solid roller lifters but was hoping to use them in my blown engine for the next barracuda.
Any suggestions on a cam profile,most off the shelf grinds peak around 600 lift with around 250@50 duration.
 
evil66 said:
Thanks for all the suggestions, i was thinking cam and port work,when i bought the cam a long time ago it was going to be for a set of j heads,which changed to a set of W2s. Even when i flowed the heads i knew it didn't have enough lift to make use of them. I do have a friend who ports heads and he has suggested a 2.08 inlet valve and port job or if going further converting them to a rectangular port.
I would like to the cam duration similar but increase the lift but thought this might be risky if staying flat tappet solid and the possibility of chewing out an agressive profile.
I do have a set of mrl solid roller lifters but was hoping to use them in my blown engine for the next barracuda.
Any suggestions on a cam profile,most off the shelf grinds peak around 600 lift with around 250@50 duration.
Click to expand...


Yeah, making them square is a PITA. I have a set under the bench that I have ported, welded, repaired and ported some more. Unless you are going to turn a 400 inch engine 8000 or more, don't bother making them square. The pushrod will get into the intake port and all kinds of crap.

Do not remove any material from the backside of the valve guide. It will make the port go more turbulent sooner.
 
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