Thread: 406 build

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right now i'm building a 406 for my 68' camaro,the 327 is a bit tired. the 406 must be streetable and must run on pump gas . so i'm going to have around 10.0:1 compression and hoping for around 440hp and 480tq. I have set of 906' vortec heads. i need to know how much machine work i need on the heads. i thinking of running voodoo cam with 227/233 dur. with 489in/504ex lift. do have have open up the valve spring pockets? and do i need to mill the guides down a bit? and also would it be wise choice to cut the heads out for 2.02/1.60's,is there major flow increase on these heads with bigger valves. much help appreciated!

10.0-1 is a bit much for pump gas with iron heads i would take the heads to a machine shop and tell them what u want for a cam and they will get the springs to go with that cam and let them do the machine work. IMO you will lose some bottom end with the larger valves.

Originally Posted by vortec king

right now i'm building a 406 for my 68' camaro,the 327 is a bit tired. the 406 must be streetable and must run on pump gas . so i'm going to have around 10.0:1 compression and hoping for around 440hp and 480tq. I have set of 906' vortec heads. i need to know how much machine work i need on the heads. i thinking of running voodoo cam with 227/233 dur. with 489in/504ex lift. do have have open up the valve spring pockets? and do i need to mill the guides down a bit? and also would it be wise choice to cut the heads out for 2.02/1.60's,is there major flow increase on these heads with bigger valves. much help appreciated!

I.M.O,you don't have cam to make 440 hp closer to 425 hp.
I don't think I would put a lot of money in a set of the Vortec heads either.
If you really want to make more hp out of your 406 heads you need to look at a good set of heads that have a port volume of 180 cc.

Originally Posted by 383 chev

10.0-1 is a bit much for pump gas with iron heads i would take the heads to a machine shop and tell them what u want for a cam and they will get the springs to go with that cam and let them do the machine work. IMO you will lose some bottom end with the larger valves.

My Michigan neighbor is right on with the 202's--If your not on it most of the time smaller valves will give you more grunt on the street!

Originally Posted by bigdude

My Michigan neighbor is right on with the 202's--If your not on it most of the time smaller valves will give you more grunt on the street!

With a 4.155 bore X 3.75 stroke he will have plenty of grunt.
With over 400 cubes he needs a larger port volume and a larger valve size for this engine to make 440 hp.

Ive built three 406's with smaller valves and they out performed the ones I built with 202's. At wide open the 202's are great! Maybe it was mojo? They also werer the 441 castings.

Originally Posted by bigdude

Ive built three 406's with smaller valves and they out performed the ones I built with 202's. At wide open the 202's are great! Maybe it was mojo? They also werer the 441 castings.

But he want's 440 hp.
There is no way he will get 440 hp with a set of 441 heads or the Vortces with small valves in them.

You are correct,alot of other things should change too!

I is no math genius but i have a buddy that ran a 406 in a 85 trans am with the vortec heads lil bit bigger cam than vortec king wants and more compression also and he ran 11.20's all day long. vortecs are (imo) a good flowing head for OEM.

when you used the 441 heads how much powere did your car make and what did you have done to the heads

Originally Posted by vortec king

right now i'm building a 406 for my 68' camaro,the 327 is a bit tired. the 406 must be streetable and must run on pump gas . so i'm going to have around 10.0:1 compression and hoping for around 440hp and 480tq. I have set of 906' vortec heads. i need to know how much machine work i need on the heads. i thinking of running voodoo cam with 227/233 dur. with 489in/504ex lift. do have have open up the valve spring pockets? and do i need to mill the guides down a bit? and also would it be wise choice to cut the heads out for 2.02/1.60's,is there major flow increase on these heads with bigger valves. much help appreciated!

To try and gain a better rod ratio get rid of the stock 5.565 rods and intall a set of 5.7 or 6.0 rods.

Originally Posted by 383 chev

I is no math genius but i have a buddy that ran a 406 in a 85 trans am with the vortec heads lil bit bigger cam than vortec king wants and more compression also and he ran 11.20's all day long. vortecs are (imo) a good flowing head for OEM.

One of the biggest problems with the Vortec heads is the exhaust to intake ratio.
To try and help the exhaust side run a cam the favors the exhaust side.
I would look for cams that have 8-10 degree's more duration on the exhaust side at .050 also run more lift on the exhaust side.

Originally Posted by maineevent

when you used the 441 heads how much powere did your car make and what did you have done to the heads

I put stainless valve in and port matched intake and heads. The big thing is to not overcam it. I used a comp extreme energy 268 cam and kit with springs and could bust my 33 loose at 30mph with a 342 ratio. Had a buddy with a 5 window with a 406 with alum heads and could dust him easy.The key is a good combo of cam -intake-carb- heads and exhaust, with a good ratio.I followed a buildup in hotrod? and they used the same setup and got 420h.p.I believe.

Originally Posted by bigdude

I put stainless valve in and port matched intake and heads. The big thing is to not overcam it. I used a comp extreme energy 268 cam and kit with springs and could bust my 33 loose at 30mph with a 342 ratio. Had a buddy with a 5 window with a 406 with alum heads and could dust him easy.The key is a good combo of cam -intake-carb- heads and exhaust, with a good ratio.I followed a buildup in hotrod? and they used the same setup and got 420h.p.I believe.

I doubt that a 268 Comp Cam in a 383 would make 420 hp with 441 heads.
Don't always believe the magizine's either.
They are in the business to sell them and the people that advertise in them are also in the magizines engine build-ups.

I,m older and more experienced and a former record holder and engine builder since 66- case rested-been there-not going to argue.