4.0 Heads

[86_cookiemonster]

I know that almost no one has used the Tom Morana stroker kit, but has anyone used the heads advertised on his site? I know that one of the biggest problems the 4.0 OHV has is it doesn't breath well. So new heads would help fix that right? I was just curious about what kind of horsepower increases people have seen.

 

[Yellowsplash]

Yes, the heads on the OHV engine are quite restrictive. With the addition of p&p heads, cam, and headers, alot of guys have made over 200-250 hp to the wheels of course with a few other supporting mods. Most people (alot of guys on rps) upgrade the cam when they install the port and polished heads. There are 2 cams that comp cams make that work well. The 410 (which is better for lower end towing torque curve) and the 422 (which builds its power slightly higher), both of which have torque peaks around 2500-3000 rpm. You must upgrade to longer pushrods with either cam as the cams are ground on reduced base circles. Smith brothers (www.pushrods.net) can custom make a set (usually ~5.550 in length). With the 422, you must upgrade valve springs which you can get installed with the p&p heads from either morana or supersix motorsports. If you go with the 422 cam, you will also want to invest in some tuning time/programmer, etc. to get the most out of it.

 

[turbo cat]

how much do those heads run?

 

[86_cookiemonster]

Bare heads cost $480 a set, and the complete heads cost $1600 a set

 

[86_cookiemonster]

Yes, the heads on the OHV engine are quite restrictive. With the addition of p&p heads, cam, and headers, alot of guys have made over 200-250 hp to the wheels of course with a few other supporting mods. Most people (alot of guys on rps) upgrade the cam when they install the port and polished heads. There are 2 cams that comp cams make that work well. The 410 (which is better for lower end towing torque curve) and the 422 (which builds its power slightly higher), both of which have torque peaks around 2500-3000 rpm. You must upgrade to longer pushrods with either cam as the cams are ground on reduced base circles. Smith brothers (www.pushrods.net) can custom make a set (usually ~5.550 in length). With the 422, you must upgrade valve springs which you can get installed with the p&p heads from either morana or supersix motorsports. If you go with the 422 cam, you will also want to invest in some tuning time/programmer, etc. to get the most out of it.

Thanks for the info, I was woundering if the head swap was worth the cash. Gues it is.

 

[AllanD]

4.0 heads restrictive? Compared to what?

The 4.0 heads have larger exhaust ports than a 5.0

AD

 

[Bird]

4.0 heads restrictive? Compared to what?

The 4.0 heads have larger exhaust ports than a 5.0

AD

The exhaust openings you see are larger, but the valves, bowls and port throats / short side radii are extremely small and restrictive - kinda reminds me of a funnel effect. On a flow bench the stock 5.0 exhaust port flows almost 1/3 more than the 4.0 at the same valve lift. The 98+ 4.0 heads are even worse - until you start porting - then all of them really pick up some great gains in flow. I used to have the flow numbers - before and after, but with the move, they're relegated somewhere to one of the boxes in storage somewhere.

Bird

 

[86_cookiemonster]

Th The 98+ 4.0 heads are even worse - until you start porting - then all of them really pick up some great gains in flow. I used to have the flow numbers - before and after, but with the move, they're relegated somewhere to one of the boxes in storage somewhere.

Bird

So, if ported are the 98 heads better than pre-98 heads?

 

[Yellowsplash]

No....your better just sticking with the 95-97 heads.

 

[Bird]

So, if ported are the 98 heads better than pre-98 heads?

In stock form, the 95-97's are better.

When properly ported, the 98's will offer more exhaust flow than the ported 95-97 versions due to the lack of that end 'flareout' and the higher exhaust velocity of a more uniform port shape. Being a smaller bowl/port to begin with, the right amount of metal can be removed in the right places instead of trying to work around the existing larger port of the 95-97 versions. I was able to consistently get 6-8 cfm more exhaust flow out of the 98's - may not sound like much, but a definite difference in performance.

The intake ports are identical between the versions and all flow the same.

Bird

 

[86_cookiemonster]

Ok thanks Bird. I am getting ready to do a 4.0 build and wanted to make sure i get the right heads.

 

[woodyedmiston]

98-2000 port shape

OK - Bird, you've just said the first thing that computes with what I know about ports and flow as it relates to the late head. The funnel shape is consistent with the notion that is in the Doug Anderson article that says Ford changed them to increase the speed of the exhaust and thereby "light off" the cats sooner. A funnel would do exactly that.

Assume, you are talking to someone who knows a bit about porting - what changes would you make to the exhaust port size that would give that higher flow number you mentioned?

Also - can I assume that was with stock exhaust valve sizes? Did you do anything to the intake side .

Don't dig through any boxes - I'll trust your memory.

 

[Bird]

OK - Bird, you've just said the first thing that computes with what I know about ports and flow as it relates to the late head. The funnel shape is consistent with the notion that is in the Doug Anderson article that says Ford changed them to increase the speed of the exhaust and thereby "light off" the cats sooner. A funnel would do exactly that.

Assume, you are talking to someone who knows a bit about porting - what changes would you make to the exhaust port size that would give that higher flow number you mentioned?

Also - can I assume that was with stock exhaust valve sizes? Did you do anything to the intake side .

Don't dig through any boxes - I'll trust your memory.

Woody - when I was talking about a 'funnel', I was referencing the pre-98 heads and the flare-out at the exhaust port mouth that gives a funnel effect which will actually slow down the flow velocity (think air flow from the small end of a funnel out to the large end of the funnel - the increase in the port area kills the velocity) The 98 exhaust port doesn't open up like that and thusly keeps the velocity up (along with the smaller port, but that reduced the top end flow) When I ported out the 98's, I basically opened up the port all the way into the bowl area, keeping the overall shape / size the same - working on raising the port roof and recontouring the short side radius to tranistion the flow out of the bowl area faster. The actual bowl was opened up and the guide reshaped to direct the flow toward the the port. I put a fairly good polish on the exhaust bowl and the port, but just a smoothing finish on the intake port with a little cleanup on the port roof. All this along with some SI-Valves undercut stem stainless valves would equal some really decent flow numbers without hurting low end performance.

There - now you have my secret recipe.

As to the chambers - using early style heads (pre-95) on a late model short block (larger dish pistons) creates a sluggish engine with 8:1 compression. When Ford redesigned the chambers on the 95+ heads, they used a 'fast burn' design that would use less timing yet still be just as efficient (hence the caution that the earlier pcms with more timing would 'burn down' the engine - didn't turn out that way, but it sounds good) Even if you were to put the early model, small dish pistons in the 99 block to run with the early model heads, if used with a later model pcm, you might see a slight performance drop due to the reduced timing.

Someday, when I have time, I'm going to build another 4.0 ohv with SOHC flat top pistons and a fully worked over set of pre-95 heads with welded up exhaust ports (98+ style) for a 10:1 compression motor with better quench characteristics and see what I can get out of it.

Bird

 

[86_cookiemonster]

Woody - when I was talking about a 'funnel', I was referencing the pre-98 heads and the flare-out at the exhaust port mouth that gives a funnel effect which will actually slow down the flow velocity (think air flow from the small end of a funnel out to the large end of the funnel - the increase in the port area kills the velocity) The 98 exhaust port doesn't open up like that and thusly keeps the velocity up (along with the smaller port, but that reduced the top end flow) When I ported out the 98's, I basically opened up the port all the way into the bowl area, keeping the overall shape / size the same - working on raising the port roof and recontouring the short side radius to tranistion the flow out of the bowl area faster. The actual bowl was opened up and the guide reshaped to direct the flow toward the the port. I put a fairly good polish on the exhaust bowl and the port, but just a smoothing finish on the intake port with a little cleanup on the port roof. All this along with some SI-Valves undercut stem stainless valves would equal some really decent flow numbers without hurting low end performance.

There - now you have my secret recipe.

As to the chambers - using early style heads (pre-95) on a late model short block (larger dish pistons) creates a sluggish engine with 8:1 compression. When Ford redesigned the chambers on the 95+ heads, they used a 'fast burn' design that would use less timing yet still be just as efficient (hence the caution that the earlier pcms with more timing would 'burn down' the engine - didn't turn out that way, but it sounds good) Even if you were to put the early model, small dish pistons in the 99 block to run with the early model heads, if used with a later model pcm, you might see a slight performance drop due to the reduced timing.

Someday, when I have time, I'm going to build another 4.0 ohv with SOHC flat top pistons and a fully worked over set of pre-95 heads with welded up exhaust ports (98+ style) for a 10:1 compression motor with better quench characteristics and see what I can get out of it.

Bird

Have you ever considered writing a book on how to build a performance 4.0 v6
seriosly is there anything about this motor you don't know?
Again thanks for the info.

 

[woodyedmiston]

Bird,

I'm a writer - maybe we should collaborate. Thanks for the SI valve answer too - I sort of kicked myself for not asking your opinion, but you said what I expected. Your description of the head work is something I can work with. I'll give you a report somewhere along the way. Maybe I'll take pictures and illustrate the book.

I'm looking for about 9.5/10.0 CR, a decent flowed set of heads, and a wide nosed, not so high lift cam, maybe build or buy some headers and find someone to tune the thing. Mine is a street truck with an auto - I just like to punch it once in a while.

My block has a bit of taper but not a whole lot of wear (even at 240k) - I was thinking of .010 to clean things up and using the older pistons and maybe the 95-97 heads - now I'm just thinking of using the 99 heads. SOHC pistons are flat topped huh - didn't know that. Maybe you have given me a solution. I've talked to Deltacams about regrinding my cam and getting the flame hardened rockers etc.

As for the rabbit trail about short stroke engines - the 4cyl I was referring to in a previous post was a destroked 2.8 liter Nissan running nothing stock and 14# of boost. It made 480hp and would keep up with the Camaro's because the weight difference was significant - and we figured out how to keep the turbo from spooling down. What was a problem was getting around the darn things - an 80's Camaro with fender flares looks like it's 10 feet across if you are trying to pass on a downhill curve.