stock 89 ho, Where to go next?

[gadget73]

P heads are very thin, so you have to be careful messing with them. Easy to hit water in those.

[Mercracer]

If you swap the whole engine you will likely have a short block which is in better shape than your factory one. You also get an engine which comes with a set of hypereutectic pistons with better rings than yours capable of taking up to a 5.50" lift or so cam with reasonable duration. Your factory pistons are plain old cast flat tops with no reliefs.
P heads can make nearly 400HP on a 351 easily and enough HP on a 302 to put a CV/GM in the 13s so it really isn't necessary to port them at all. For an inexperienced person, the odds are better that you will mess up the flow rather than improve it with a home port job. I would not shave them if you plan to use nitrous. They are a lean burn design and the combustion chambers are small as is.

[gadget73]

He's got an 89 Mark VII motor, same as an 89 Mustang. Forged pistons, valve reliefs, etc.

[zoomie]

Porting p heads is tricky but blending and polishing the bowls is easy, but as previously stated i read alot and even emailed tom moss on the subject . i never did get around to finishing the last set but ill be doing another set this summer. but yeah when porting any head read read and read some more ask alot of questions. and if you do decide to dy, make your first set free i learned a 50 dollar head porting lesson with my e7 heads. Also I have apersonal preference for forged pistons mainly because I plan on running nitrous at sme point also depending on what direction you want to go in a 306 with forged pistons short block can usually be had for around 500 bucks already to be assembled

[jaywish]

Hi All,

I finally bit the bullet and had my old rotted out piecemeal duals replaced with stainless. 2.25" pipes, H-pipe with Highflow Magnaflow cats & 2010 Mustang GT mufflers. The sound is nice. Not real loud but much louder than stock and the idle sounds great.

The most important thing was the complete resolution of my reduced high end power issue. I had been mentally wrestling with the lack of power for about a year. I thought an exhaust restriction was the likely culprit. Running the vacuum test showed that the vacuum increased at a fast idle. That is supposed to indicate a free flowing set of pipes. In fact one of the four cats was part clogged. Perhaps that test only works with a single exhaust?

My friend with an LSC had to ream out his cats as his clogged also. I think they all may be giving up at this stage in their life so think twice about using those old mustang/Lincoln H-pipes.

Should I advance the timeing a few degrees? Downsides?

Jay

[gadget73]

Try it. If it pings, back it down. Thats about the only possible downside.

Cats last normally almost forever if the engine is running right. Unfortunately a lot of motors don't get regularly scheduled tuneups and such, and end up running too rich or lean, which kills the converters. The set I pulled off my Mark VII at 225k were not clogged at all. The case was cracked on one of them though, and the pipe around it wasn't all that hot. I realize this isn't the typical situation though, and I'd expect that the 100k mile car that has never had a tuneup in its life may well have clogged converters.


Question for you. In your sig it says "rear air ride", do you mean the factory air shock auto-level stuff, or did you fit 90s Towncar air springs back there? My car has the auto-level stuff, but at some point I'd love to put air springs on. Just curious if anyone else has done that.

[jaywish]

Hi,

Well I can't speak to the engine maintenance prior to it going into the wagon but afterwards the car got regular maintenance. I did have one side running rich for an undetermined period of time as one of the injectors was stuck open. I didn't find that one untill another one failed shut. I didn't get the clog for 15k or so after that was rectified.

As far as the air ride goes, I just installed the regular factory auto level air shock setup. I liked the air springs I had in my 93 GM sport. Do you think it would make a significant handling difference?

Also you used a cvpi steering box. Is there a difference, I ask because I'm likely to change my box in the fairly near future.

Jay

[gadget73]

I'd expect slightly better ride quality with actual air springs, but I doubt it would handle better. I don't have the auto level hooked up currently, but I did like it when it was there. I was just thinking actual air springs would give me better rear shock selection since I wouldn't be limited to only a small handful of air shocks. I could also consider those load helper bag things that sit inside the coil, and just keep the normal shocks. Lots of options. The air spring thing is somewhat appealing because I don't know that anyone has done it before.


The police box has a little heavier wheel feel to it. I dont know if theres a really significant difference with box body police boxes, but by the 90s it was fairly pronounced. Sometime in the mid 90s the lines and input shaft changed on the box though, so if you want a really new steering box, you'll have to get creative. My pressure line is custom made from part of the stock line and part of the 2000 hose, and the coupler is built from the 00 car and my 86, with a universal rag joint repair kit holding the parts together.

[jaywish]

You are right about the shock selection. Plus I think the air bags are controlled independently where the current shock setup fills/deflates both simultaneously. I'm told this is not optimal when going around turns. One of the guys here found me a rear sway and that should be going in next.

I don't mind the light wheel feel but I was thinking the pi might have had a tighter ratio.

[BerniniCaCO3]

Just for more data.
Last spring I did my HO swap.

I have a 1990 wagon, put in an HO motor, with the 4-spray injectors, HO computer, stock HO intake and throttle body (wanted to keep low end torque, so no need for gt40 intake), BUT found gt40 heads cheap and installed them, and, put in an explorer cam.
It seems to run just fine. Stock speed density computer from a 1990 lincoln.
Around town my fuel economy is... poor. But I finally, finally got a decent long highway trip last weekend, and averaged 18mpg. That was with winter fuel, and admittedly, going 80mph half the time, with enthusiastic on-ramp accelerations. With more conservative driving I probably could have/ would have done better; but if I wanted to get into hypermiling, I shouldn't be driving a 22 year old panther to begin with....

This month, I'm putting in a new transmission --really just to learn about them, I'm rebuilding it-- but I'm putting in a slightly higher stall/ higher torque multiplying converter, and putting in the mustang transmission governor (inside that tailpiece on the trans), both of which should put the engine a bit higher up in the power band. Because going to 3rd gear and only doing 700rpms on an on ramp, is not ideal, even with the explorer camshaft to keep some low end torque.

I'm also putting in 3.55 gears.

And then I think I'm calling it a day for modifications; leaving only body work and a paint job left.

[turbo2256b]

I prefer the GT40 heads so do some serious races I have worked with. As for flow data I have found done on the same bench there dosent seem to be any big differance in CFM P only better than less than 5 CFM. The 40s do have the atvantage of being able to install larger valves which the larger ports like.

[BerniniCaCO3]

how different is the explorer camshaft from the HO camshaft?
I had trouble finding a solid answer.
How badly tuned might I be running, using an HO computer but an explorer camshaft?

I only found one torque/rpm graph, from someone here years ago and using who knows what data,
which seemed to show that the HO and explorer camshafts were virtually identical, with the explorer producing very modestly more torque at the low end and very modestly less torque at the high end (say 3000+) versus the HO.

[turbo2256b]

IT WILL WORK think a few on here have done that

[BerniniCaCO3]

It's what I've got now, and it seems to work.
Wondering if it's just working badly (and I'm not experienced enough to realize it),
or if it could have worked much better with the HO.

[zoomie]

Just a tidbit,but when u put the new gears in, make sure to put the right trans gear in so your speedo won't be off,also adjust your throttlecable a bit I have mine just a hair past mid and between full and mid . After that you wil be able to do 55 in drive with no issue , I usually don't do od till 65 or so. 700 rpm going on ramp? That seems awfly low