Runner size of 3L split-port HEADS

[SicSE]

Does anyone know it? Especially on the intake side. I'm sure this has been covered, but I've been unable to locate the info.

I ask because the runners of my SVT heads look painfully small for the larger 3L valves that I'm thinking of getting installed. I would expect the 3L split-port heads to have larger diameter runners to accomodate the larger vavles. If this is the case, it would greatly cut down on the time I would spend porting... since it would be more of a reshape, than overall size increase.

So I'm thinking I may be better off dropping a set of 3L heads on, instead of bothering to have the 3L valves & seats put in my 2.5L heads. I don't want to lose the compression of the hybrid, but if the runners in the 3L head are larger, it might be a worthwhile trade-off. Thoughts?

I know that I'll need an electric water pump... which is something I was planning to do eventually anyway.

 

[Harrry]

Does anyone know it? Especially on the intake side. I'm sure this has been covered, but I've been unable to locate the info.

I ask because the runners of my SVT heads look painfully small for the larger 3L valves that I'm thinking of getting installed. I would expect the 3L split-port heads to have larger diameter runners to accomodate the larger vavles. If this is the case, it would greatly cut down on the time I would spend porting... since it would be more of a reshape, than overall size increase.

So I'm thinking I may be better off dropping a set of 3L heads on, instead of bothering to have the 3L valves & seats put in my 2.5L heads. I don't want to lose the compression of the hybrid, but if the runners in the 3L head are larger, it might be a worthwhile trade-off. Thoughts?

I know that I'll need an electric water pump... which is something I was planning to do eventually anyway.

Now if porting is completley out of the questions..then 3L heads would be in YOUR situation a plus. Since your SE heads don't have the EH process as the svt's. Svt heads are EH on both runners.(98 models are different).

So going to a larger runner area...such as the 3L head with 3L valves. I would find this the best for your situation. Why don't you have the heads decked...that way you would still sustain your HC your looking for and it would be way cheaper then getting all the ports ported and grinded for the 2.5L heads to accept the valves? :shrug:

 

[SicSE]

Why don't you have the heads decked...that way you would still sustain your HC your looking for and it would be way cheaper then getting all the ports ported and grinded for the 2.5L heads to accept the valves? :shrug:

I don't want to do any ground breaking as far as valve-to-piston clearance goes. I have zero desire to clay this thing, (which I would definitely do if there were any milling involved). In other words, I'm not considering milling of any kind at this point.

The heads that the 3L valves would go into, are SVT heads.

I will be doing some porting either way, (and doing it myself) ... just a lot less on the 3L heads, if the ports are indeed larger.

 

[Harrry]

I don't want to do any ground breaking as far as valve-to-piston clearance goes. I have zero desire to clay this thing, (which I would definitely do if there were any milling involved). In other words, I'm not considering milling of any kind at this point.

The heads that the 3L valves would go into, are SVT heads.

I will be doing some porting either way, (and doing it myself) ... just a lot less on the 3L heads, if the ports are indeed larger.

See don't forget the oiling issues have with the 2.5L heads. Which was a main concern for others years ago when considering the 3.0L upgrade. The oil drains...are smaller due to redesign from the original porches 2.5L engine. Which left the 2.5L obvious short of oil in the oil pan...

I already assumed from your prior work that you are well educated enough to do the porting yourself. (plus it's damn cheaper). I honestly would go with the 3L heads and still do some porting of the ports. Exhaust and intake size. Might as well...you have them sitting around already.

I saw your other thread...but i'm running out of time and my lady is hovering over me right now. Will you be cleaning up the chambers? unshrouding? at all with either head?

 

[SicSE]

See don't forget the oiling issues have with the 2.5L heads.

Well, remember that I'm currently running a hybrid. I'm only about 15k & 2 years in, but no issues yet.

I honestly would go with the 3L heads and still do some porting of the ports. Exhaust and intake size. Might as well...you have them sitting around already.

The heads that I currently have are SVT's. I'll be journeying to Pull-A-Part if I decide to go with 3L heads.

Will you be cleaning up the chambers? unshrouding? at all with either head?

Definitely both... especially if I do the SVT's - the intake valve area can use some serious work - especially the secondary port being so closed to basically a wall. Everything else will get smoothed down if not completely grinded away.