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-   -   CONFUSED-what blocks will '99 PI heads fit on? (https://mustangboards.com/modular-4-6l-tech/31381-confused-what-blocks-will-99-pi-heads-fit.html)

skylark 06-30-2008 04:32 PM

CONFUSED-what blocks will '99 PI heads fit on?
 
I have been looking for either a 5.4 or a 4.6 aluminum block for a rebuild. Karkraft.com has both but they each have flat top pistons for 4V heads, NO NOTCHES. So I would need different pistons or is there enough material to notch for a performance cam?
How about the front covers, what interchanges with what? Will any front cover work on a block that was once wearing a set of 4V's?

I also ran across a great article from what I was able to see about Hitech motorsport working on a 5.4. From what I caught the motor had a PI intake with adapters and made 95lbs./ft. more than the 4.6 at 2500rpm! Do 12" wide and 345/17's fit under a new edge! LOL
Not yet hooked for a "real" computer I could not read the article and have it saved at a friends for next week when I am hooked for a laptop I bought. Then I will be able to read the entire article. It seems all Hitech did was tune the 5.4 to their specs, 13:1 AFR, not sure of the timing but usually Hitech tunes for 87 octane and about 23* of total timing but not sure the 5.4 likes the same as the 4.6. The 5.4 came in at 12.3:1 AFR. After tuning the 5.4 made 30whp more than the 4.6 also!

The block head thing has me confused as I thought 2V heads could fit a 4V block or is that simply due to the non-notched pistons that were the reason but what about the front cover?
I know guys have the aluminum blocks and 2V heads, thought nthey did anyways! Anyone?

bassman97 07-01-2008 06:59 AM

Modular blocks aren't head specific really so 2V, 3V, and 4V heads can but put on the same block. If you are worried about PTV, bolt the head up and check for clearances. If it's too tight, Isky Cams makes a piston notching tool that you put in place of the valves and then you hook up a drill to it.

na svt 07-04-2008 08:11 AM

2v heads on a 4v block will result in the compression being 1 point higher than than what the 4v heads provided. So, a 9.8 to 1 cobra motor would end up with roughly a 10.8 to 1 compression.

I personally would stay away from any of the 4v blocks and build a motor with 2v pistons w/valve reliefs.

skylark 07-04-2008 08:18 PM

I guess if I can't find a complete 5.4 and I want to build a motor could an aluminum 4.6 from Karkraft.com be used with my 2v heads and my front cover? Actually I was thinking of using Hitech heads. If I go 4.6 might as well drop the weight as handling is important also. So will those aluminum blocks they sell work with a set of 2V heads and my front cover?
SVT you seem knowledgeable so I would like you to look at this set-up and critique it please?.

Aluminum 4.6 block. Forged rods and pistons, maybe crank if I could find a good used one. I know the forged cranks are 2lbs. heavier and I will likely not need thnat strength there but I would like to have a motor ready to exchange with mine when the time is right.
10.5:1 compression or a bit higher. Hitech tunes their motors/cams on 87 octane and about 23* timing as they say the extra power from 93 is not worth the expense but I see it as insurance. Since I like 25/26* timing at WOT a 10.5:1 on 93 should not be a concern, especially if the heads had polished chambers, run a 160/180*stat and 1 range colder plug. I am not suire if the 160* stat would go into closed loop. Anyone know the temp required for that?
Hitech heads. Hitech stage 2 cams. Now the big one I have avoided, LT's. Hitech says without a doubt even if the dyno says 4-10whp!
So what ones? I have an auto so it seems MACS will fit an auto and are not too costly. Then again with the motor out it may be easier to change them as I would required to farm all work out due to a disability, 3 back surgeries. Other choice is Hookers which seem better but not sure?

Gears. I have 4.10's now but with the 5.4 I was going with the stock 3.27's. I almost think 4.30's with the 4.6. I can't drive very far anyways, maybe 100 miles at a time. I have no-one to help drive either so maybe go 4.30's and could change back if needed for a long trip as I have a new differential coming next week, $175. for 27 spline like stock.

I have 2 converter choices, reworked stocker, 2800rpm stall, maybe 3000 and a 10" unit with 3200-3400rpm stall that has the tune that driopped .2 and locks 2nd gear even at part throttle, that is the one I would use.

My intake is an SVO port matched to PI heads, stay with that either way, good for high revs or volume that a 5.4 could use.(4.6).

Miss anything and sound OK? THX!

Oil pump?
Probably 24lb. inj's as I believe mine are leaking, hard starts when warm and has sat. Need to open throttle which is dual blade 57mm.

na svt 07-04-2008 08:56 PM

The 2v heads and front cover will work with the Teksid block. Long tubes are a must. As for the rest of your combo, it looks real good, but with an auto I'd go with a stroker.

skylark 07-05-2008 04:54 AM

Stroker or the 5.4? Stroker may be easier. Kits readily available and what size is best. You know, best rod length/stroke ratio's and all the stuiff I don't know about? Thx.

na svt 07-05-2008 06:44 AM


Originally Posted by skylark (Post 340763)
Stroker or the 5.4? Stroker may be easier. Kits readily available and what size is best. You know, best rod length/stroke ratio's and all the stuiff I don't know about? Thx.

4.6 Strokers from Modular Performance or Modular Powerhouse have proven to be very good.


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