Head cooling mod and crossover delete

[OU812IC]

Since I am putting the centri on I need to do something with the coolant crossover. I refuse to pay the money for the Vortech tube. The On3 kit looks pretty nice and the price isn't to bad.

It seems there are two different paths to take for the head cooling mod. I see some that tie into the rear freeze plug on the back of the head and tie to the passenger head and then the heater core. Looks like a real PITA, I am not interested in this version, at least not tying it into the passenger head. I only want to do the driverside and run it up. On Cobras it looks like they can tie into the plug that is kinda on top of the head next to the intake port.

I have not torn into it yet and trying to get the parts together. It I do the imrc delete and egr delete do you think there is enough room to use the port on top? I looked back there it doesn't look like there is a whole lot of room in its current configuration. My hope is that after the deletes it will free up some space. If someone has done the imrc and egr delete with a 97/98 intake can take a pic of driverside back corner that would be great!

Couple more weeks and I am going to be raising hell in the garage! If you have seen any of my posts I have a lot going on. Ordered pump and injectors. New clutches and bearings for the posi, I got the stub shaft/output bearings and seals too for the pumpkin. Found a 93 driveshaft in Ohio for $150 but I have run out of money for another week. My wife is about to kill me, she hasn't talked to me much in the last week. After 23 years we both could use a break hahahaha

Thanks in advance for any help you can provide.

Du

 

[97Mark8]

I know it's a little off topic but I would really consider upgrading to a 96-98 Cobra Intake, the Gen 2 Mark 8 intake with it's 8 runner design is literally THE worst flowing intake manifold that I know of for any 4.6 4V with B heads. The Gen 1 Mark 8 intake with 16 runners definitely outflows the Gen 2 intake significantly. I bought mine for only 275$ total for the upper lid & lower plenum, you should be able to find one typically for 300-500$. You shouldn't have any fitment issues to my knowledge with the 96-98 Cobra Vortech Centri kits some others have used.

 

[97Mark8]

This is the intake I started with that I paid $275 for

 

[OU812IC]

Superchargers online is still holding my order for the mounting and oil line kit. The latest is that they are waiting for the belt to come in.

Guess what I got today... $230

Includes bolts and delete plates. The hat has been powder coated black(lost the pic). The lower is still el'natural

Looks like someone did a little porting and polishing.

View attachment 828474258

View attachment 828474257

View attachment 828474256

 

[OU812IC]

Since I am doing the Paxton thing, do I want to make this a short runner? I did some reading about doing the modification. Is it really worth the effort? I was thinking to make the cuts on top essentially cutting the runners in half.

 

[driller]

By most accounts, the most you want to remove from the runner length is approximately 1-1/2".

With boost, it is arguable if shortening the runners is beneficial.

 

[chris2523]

depends on your shift points.
if you plan for 7k and have cams to support that, then sure.
otherwise, no, i don't think its a good idea.
especially in our heavier platform.

 

[OU812IC]

Stock cams target is 8lbs of boost. Cooler or meth, not sure on that part yet.

 

[chris2523]

then no, i would not advise shortening the runners.

 

[OU812IC]

Thanks, I will leave good enough alone.
I am off over thanksgiving and the plan was to start the project then. Since I am STILL waiting for the bracket kit it looks like I am going to have to tile the kitchen floor instead.

 

[97Mark8]

Oh geeze here we go again. Another guy with stock cams and a unported intake trying to give his 2 Cents about why shortening the runners wont add power. Here are the FACTS: 1 1/2" seems to be the norm for length of runner material to remove on a N/A application. Of course it would be a good power adding mod either N/A or running boost, anyone who wants to argue that is just silly. An engine is essentially just a large air pump, so using common sense how would improving the airflow of a intake manifold not be an improvement? That's my main problems with some of the info on here, you guys tend to just repeat what one another says without actually trying a mod. If your goal is to run 8 psi I bet you see a 20RWHP difference with the shortened runners... lol. Secondly, turning 7K rpms IS NO BIG DEAL AT ALL with these motors. if someone is questioning if their 4.6 4v is going to be turning 7k or not they either don't want to make power or don't race it. FYI my car shifted at 6800 with 4.10s and the stock tune. With just a tune and a cobra intake their are people making power to OVER 7k with the STOCK cams. Its just really all common sense. BTW OU812C if you want a cheap cam idea go with 96-98 cobra intake cams they have roughly 20 degrees more duration on the intake side than the stock Mark 8 cams do. Ive literally seen 20 rwhp dyno proven on a stock 4.6 4v with 96-98 cobra intake cams. You obviously just run the stock springs (if you have a 95 and later), retainers, valve locks, etc as stock and they are a direct swap. You can find these for about 200$ on ebay. Also, why do I see so many comments about losing bottom end? Almost everyone I see worried about losing bottom end has Gears and a High stall converter, with both of those mods you don't even really have a "bottom end", that's the whole point of having a 3.73 or better gear and a high stall converter.

 

[chris2523]

Nah. I've seen mark viiis with cobra intakes slow down in the quarter mile shifting that high.
The mark viii cams just don't seem to make power quite that high.

And on boost. Many people claim shortened intake runners don't make the same extra power under boost that they do under the same NA conditions.

This is not off the cuff. I've looked into this a few times now.

Also. Neither driller nor I have stock cams btw.

 

[97Mark8]

Do you have any dyno numbers to back up the less HP with forced induction with a short runner intake? Because personally, I'd love to see them. Also, I doubt you have anything more than a set of 96-98 cobra intake cams. Also, driller may have aftermarket cams, love his car and it's fairly quick too, but he's not the end all be all of 4.6 4v knowledge. Half of the people worship Kstromberg who could only run mid 13s (nothing against him or his car and not trying to be it sound rude), also speaking of him, wasn't he the one shifting at over 7k with a stock unported cobra intake, and still making more power and dropping time off of his et while doing it. And if that isn't enough a Mach 1 (same intake and exhaust cams as the mark 8) will DEFINITELY make power over 7k if you want to argue it your incorrect, so why wouldn't it in a mark 8? Yes I realize a Mach 1 has C heads, yes I realize a Mark has B heads, but with 4 valves per cylinder and some amazing flowing heads like the 4v has you can't tell me it won't make power at a high rpm like that with stock cams. Look at how many people on youtube are shifting at 7k or higher in multiple 4v vehicles, Marauders, mark 8s, Mach 1st the list goes on and on. If you slow down with a cobra intake swap 99% Guarantee it's because you have the stock 3.07 open rear and stock converter so it hurt their bottom end , and even then that's easily corrected

 

[OU812IC]

I am going to run 410 gears and a posi (sitting on the bench) and a stock convertor. Get it tuned with that. After I get the data I am going to send it to the convertor mfg (tbd) for a recommendation. At the moment I don't have the intention to shift past 6500. That seems to be the norm for most of stock engines I have read with stock mark cams and cobra intake configuration with imrc deletes. That said, if the dyno shows different then I will reevaluate at that time.
Someday.... I want to rebuild the lowerend with forge components to be able to take more power/boost. At that point I will mess with the cams. I don't feel like messing with them in the car. Seems like a real PIA. If I am going to mess with the cams I am going to degree them as well.
However you never know what the future tells. I may get bored next winter and who knows what will happen.
I think for the first pass I have a lot to do at the moment. Boost, Cobra Intake, egr delete, cooling mod, exhaust of some kind, plugs, AFR and Boost gauges, meth or air cooler and who knows what else i need to do just with the loose ends this stuff creates. Guessing I will need valve cover gaskets too.
Now that I put this all out there.... holy crap is this a list
Anyone bored in NE IL or SE WI? Got beer and a good cook!
STILL waiting on the vortech braket. WtF, I ordered the kit October 8th!

 

[OU812IC]

Oh!
While I do plan to run it at the track once in a great while I am not concerned with track ETs. Don't get me wrong I'll be pissed if it runs 13.8 - 14 with a good launch after all the work and money. My kid just bought a 2000 GT with centrifugal and after cooler. I think he was getting nervous that his 408 foxbody coupe was going to have trouble. Hahaha.