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porting heads soon, answers welcome.

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mrkindweiler

· I love my 3.9 and Jesus
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Discussion starter · #1 ·
very soon i'll be buying a set of beeffy iron heads for my 3.9 to have ported.

should i spend the extra money to have them CNC machined or have a local dude do it without the CNC?

also, I want to get more lift out of the valve train (without getting a new cam) if it gains me more powaaa. My current cam profile is 208*/214* .512"/.520" (at 1.6 ratio which i have) on a 114 LSA, if i ditched the 1.6 rockers and went with 1.7s with stronger springs, that would significantly increase my lift, but i was told i would need to check my piston to valve clearance. how would i do that once the heads are off? and would that hassle be worth it if any? as in the power increase from the higher lift?

thank dudes.
 
Discussion starter · #4 ·
#6 ·
Good luck finding someone that has a CNC program for 3.9 heads. I would get the heads cleaned up by hand and good valve job and call it quits at that. Leave the valve train alone. I don't think the extra lift, if even usable, would be worth the $$$.
 
#7 ·
mrkindweiler said:
haha, so id pretty much have to buy the 1.7s before before checking the "P2V"

and if they dont clears did i just waste my money?
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If they don't clear you can cut reliefs in your pistons, with the pistons still in the block IIRC. Hughes sells a tool to do this I think.

Do the 3.9l have pistons like the 5.9l or the 5.2l. If they are like the 5.9l you should be OK. If like the 5.2l ... MAYBE not.
 
#8 ·
id say leave the lift as it is. motor wont be in that upper powerband much anywho...port the heads by hand. polish everythingcept the exhaust side. leave that a little rough. gasket match everything. even the new headers to the heads. blend it all in. also, deburr the combustion chamber, and unshroud the valves. get the heads decked .020 off, and then get .020 shorter pushrods. this will increase your CR a bit.
 
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#10 ·
realdeal7369 said:
id say leave the lift as it is. motor wont be in that upper powerband much anywho...port the heads by hand. polish everythingcept the exhaust side. leave that a little rough. gasket match everything. even the new headers to the heads. blend it all in. also, deburr the combustion chamber, and unshroud the valves. get the heads decked .020 off, and then get .020 shorter pushrods. this will increase your CR a bit.
Click to expand...
Why would you leave the exhaust a little rough????? that trick is done on the bowl on the intake when using a carb on a street motor to prevent fuel puddling at low rpms.You want the exhaust smooth for good exhaust flow out of the port.

I would recommend just take the heads to a good machinist and have him port them if looking for most hp out of the heads.If just want a little better flow then a hand port job can be done by you,but you can fuck shit up if you don't know what you are doing.If you remove to much or in the wrong area you will actually hurt yourself.So get a book or vid on how to port yourself or a friend who knows what the fuck they are doing.I gotta buddy who knows what he is doing and we are gonna hand port some stock maggy heads for a 360 I'm thowing together in a gen II for kicks.

DEPUTY
 
Discussion starter · #11 ·
slammedR/T said:
Why would you leave the exhaust a little rough????? that trick is done on the bowl on the intake when using a carb on a street motor to prevent fuel puddling at low rpms.You want the exhaust smooth for good exhaust flow out of the port.

I would recommend just take the heads to a good machinist and have him port them if looking for most hp out of the heads.If just want a little better flow then a hand port job can be done by you,but you can fuck shit up if you don't know what you are doing.If you remove to much or in the wrong area you will actually hurt yourself.So get a book or vid on how to port yourself or a friend who knows what the fuck they are doing.I gotta buddy who knows what he is doing and we are gonna hand port some stock maggy heads for a 360 I'm thowing together in a gen II for kicks.

DEPUTY
Click to expand...

sweet! im looking for the most power so i will look into a machinist around here to CNC them. but i dont know if the stock 3.9 mag heads have enough meat to port? i also heard they are prone to cracking. any info on that?
 
#12 ·
mrkindweiler said:
sweet! im looking for the most power so i will look into a machinist around here to CNC them. but i dont know if the stock 3.9 mag heads have enough meat to port? i also heard they are prone to cracking. any info on that?
Click to expand...
I haven't dealt much with the 3.9L heads so can't say yes or no,but I doubt they will cnc the heads probably do a hand port and polish.Which like I said is fine from a good machinist,my R/T heads were hand ported by Stan Brown and those bastages made 415 whp on my 408.

Wait 15min's and hskRT will be in here to tell me how I'm wrong and what he did better than anyone on here.:stirthepo


DEPUTY
 
#13 ·
slammedR/T said:
Why would you leave the exhaust a little rough????? that trick is done on the bowl on the intake when using a carb on a street motor to prevent fuel puddling at low rpms.You want the exhaust smooth for good exhaust flow out of the port.

I would recommend just take the heads to a good machinist and have him port them if looking for most hp out of the heads.If just want a little better flow then a hand port job can be done by you,but you can fuck shit up if you don't know what you are doing.If you remove to much or in the wrong area you will actually hurt yourself.So get a book or vid on how to port yourself or a friend who knows what the fuck they are doing.I gotta buddy who knows what he is doing and we are gonna hand port some stock maggy heads for a 360 I'm thowing together in a gen II for kicks.

DEPUTY
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sorry, meant intake.
 
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#15 ·
slammedR/T said:
I haven't dealt much with the 3.9L heads so can't say yes or no,but I doubt they will cnc the heads probably do a hand port and polish.Which like I said is fine from a good machinist,my R/T heads were hand ported by Stan Brown and those bastages made 415 whp on my 408.

Wait 15min's and hskRT will be in here to tell me how I'm wrong and what he did better than anyone on here.:stirthepo


DEPUTY
Click to expand...

the 3.9 heads as far as i know are not prone to cracking. and cleaning them up and porting them is the same as the v8 heads. totally agree with doing it by hand. just take a little bit of time, and work with a dremel or a drill, with a carbide bit set. thats what i used for the 318 heads i have.
 
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#16 ·
realdeal7369 said:
the 3.9 heads as far as i know are not prone to cracking. and cleaning them up and porting them is the same as the v8 heads. totally agree with doing it by hand. just take a little bit of time, and work with a dremel or a drill, with a carbide bit set. thats what i used for the 318 heads i have.
Click to expand...
Hey realdeal I would give you some POS. rep for some good info but the fuckning thing won't let me,so I'm telling you POSITIVE REP HOMIE :D


DEPUTY
 
Discussion starter · #19 ·
slammedR/T said:
I say spray it at the track,then port heads,adjust the A/F ratio as the increased flow will change it,then spray again at track to see actual gains.


DEPUTY
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time to start saving dough. need to port shit outta kegger, get 50mm TB on, and get the spray kit on. :D

how long it take you to install spray kit? im guessing it will tame me double that time.:jester:
 
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mrkindweiler
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