Looking for opinions on the "best" Head/Block combo?

[VT_4G63]

As the title states, I am looking for opinions on what the "best" 4G63 Block/head combo is amongst the various combinations possible by mixing 1G, 2G, 6-Bolt, and 7-Bolt heads and blocks.

I have the parts to pretty much put together any block/head combo possible amongst the various combinations of 4G63 parts.

I'm going to initially run an MHI Evo 3 16G with all the necessary supporting mods. For cams, I'm starting out mild with GSC S1's. Eventually, I might go with GSC S2's.

My goal for the car is to be a fun street car, not a daily or a track car. I'm looking for between 350hp-450hp.

I have an EVO 3 intake manifold if I end up going with a 2G head, whether it's on a 6-bolt block or 7-bolt block. Otherwise, with a 1G head, I'd go with a 1G intake manifold. Either way, I'm running an FP exhaust manifold.

I also have the means to run a 1G 7-Bolt head on a 7-Bolt block if that combo is considered preferable.

My takeaway has always been that 6-Bolts are more stout and 7-Bolts are more evolved (factory main girdle, crank sensor, etc.).

I take "crankwalk" with a grain of salt; I'm aware of it, but I'm not basing my build around it.

Basically, I'm looking for opinions on what combo of 4G63 head/block people would go with if given the option, based on previous experience.

Thank you

 

[92AWDHX40]

There is no best too many considerations on anyone's build . Tuning will always play a big part. Other wise putting parts together is one thing but they all gotta play nice. No real answer There in my opinion.

 

[randman2011]

At that power level I'd definitely stick with a 2g head and EVO 3 intake manifold. I doubt it really matters what you put underneath it. There are plenty of theoretical advantages and disadvantages to the different bottom ends but I'm still waiting for any of them to manifest. FWIW I've always personally had 7 bolts, except for one 6 bolt that had come in my Talon and the swap had been botched, so out it went.

 

[Spleen8urLSX]

Any combo listed will do for your goals no problem, really no advantage or disadvantage to either in that range. If it were me I’d use whatever block and head you have that’s in the most workable condition and run that.

 

[CrackedDSM]

I'd personally avoid the FP Exhaust Manifold and go with an Evo 3 Exhaust Manifold or just a good old fashioned ported 2G. My least favorite exhaust manifold for a 16G or 14B sized turbo is the FP Mani. Makes it laggier and focuses more on top end which the 16G isn't gonna have unless it's a billet job or has that fancy new turbine wheel.


Other than that, posters above have got it. If you have a 1G head and only a 1G Head, grab a cyclone IM and properly actuate it. Has a huge increase in torque, very little(1-3cfm on an HX40) loss of flow up top compared to a stock IM. Good stuff. Evo 3 IM and 2G head is also a stellar choice.

 

[97egl]

If you are actually shooting for 450 whp I would go with a 6 bolt bottom end. The 7 bolt rods are going to be pushed to their limit at 450whp. You will also be pushing the transmission to its limits at that power level. So if you just want a fun street car I would shoot for 350hp and run a 2g 7 bolt bottom end with the 2g smaller port head as well as the evo intake. Its pretty cheap to get there and you shouldn't have to worry to much about the power breaking parts. Once you go beyond that the weak links start to break

 

[Spleen8urLSX]

If you are actually shooting for 450 whp I would go with a 6 bolt bottom end. The 7 bolt rods are going to be pushed to their limit at 450whp. You will also be pushing the transmission to its limits at that power level. So if you just want a fun street car I would shoot for 350hp and run a 2g 7 bolt bottom end with the 2g smaller port head as well as the evo intake. Its pretty cheap to get there and you shouldn't have to worry to much about the power breaking parts. Once you go beyond that the weak links start to break

I take it you’ve broken 7 bolt rods pushing them to that kind of power?

 

[VT_4G63]

If you are actually shooting for 450 whp I would go with a 6 bolt bottom end. The 7 bolt rods are going to be pushed to their limit at 450whp. You will also be pushing the transmission to its limits at that power level. So if you just want a fun street car I would shoot for 350hp and run a 2g 7 bolt bottom end with the 2g smaller port head as well as the evo intake. Its pretty cheap to get there and you shouldn't have to worry to much about the power breaking parts. Once you go beyond that the weak links start to break

450whp might be a little wishful thinking, and that number exceeds what I originally set out to obtain, but you know how it goes.
From my research I've somewhat taken away that about 400hp is where you start to see the weak links in the drive train start to break. Obviously I'm sure everyone's mileage must vary there a bit. I'm going to try and hover a little below that number as you suggested.

 

[VT_4G63]

Thank you everyone for the informative opinions, that is exactly what I was looking for.

I think I might run a 7-bolt with the EVO 3 intake manifold, and keep my 6-Bolt motors as backups.

I've heard/read a couple other places that the FP Exhaust manifold might not be ideal for my setup so I am probably going to rethink that component as well.

I will probably hunt for an EVO 3 exhaust manifold and see what I can find. Or try my hand at porting a 2G Manifold; never done that before.

Thanks again, everyone.

 

[EC17PSE]

400hp is fine on a stock block. Many have done more for so many years and lifed to run another race, just remember torque will kill it far faster. They hate high compressive loads and will bend so limit torque and you wont have an issue. Try work towards adjusting it so boost kicks in a big more linearly and this will help.

Many in the 5-700 range on stock parts and some lived and some dont but if its tuned correctly and worked just right you can make the parts just about hold on ok.

 

[randman2011]

I've heard/read a couple other places that the FP Exhaust manifold might not be ideal for my setup so I am probably going to rethink that component as well.

I will probably hunt for an EVO 3 exhaust manifold and see what I can find. Or try my hand at porting a 2G Manifold; never done that before.

Thanks again, everyone.

I was going to comment about the FP manifold along the same lines, but I haven't personally run one so I left it to others to chime in.

I STILL don't have a definitive answer on the various EVO exhaust manifolds, but FWIW I have an EVO II and it seems to provide the same benefits as the III. From what I have gleaned, they are the same design but of slightly different metallurgy.

 

[pboglio]

FP manifold works well with a 16g. Having it ceramic coated and adding some type of heat shield to it makes a huge difference. It does push the power slightly up higher but it works great with the EVO 3 intake manifold and a decent set of cams. That would make a solid 350 w.h.p. with some reliability built-in. Around 400 w.h.p. depending how it's tuned the transmission does start having issues and had I to do it over again I'd have detuned it back to easy 350 w.h.p. and enjoyed the car more. Keep it simple.

 

[97egl]

I take it you’ve broken 7 bolt rods pushing them to that kind of power?

I was a little under 500 when I broke one and 2 of the others measured out of spec. I only had a couple months use on them so probably 30 passes or so at that power along with street driving. I had been at 350 for 2 years before that with no issues and the rods had been checked and ARP bolts installed before going up to 500. I was also winding the engine up higher at 500 to take advantage of the cams and larger turbo I had so the RPM may have played a part too but I think 350 is a good solid number for a street car to be at. If it's mostly a track car I would say very low 400s should be ok for stock bottom end but those engine are also getting torn down and checked more often than a street car, so if parts are getting stressed hopefully it's caught before there's a window in the side of the block.

 

[Spleen8urLSX]

I was a little under 500 when I broke one and 2 of the others measured out of spec. I only had a couple months use on them so probably 30 passes or so at that power along with street driving. I had been at 350 for 2 years before that with no issues and the rods had been checked and ARP bolts installed before going up to 500. I was also winding the engine up higher at 500 to take advantage of the cams and larger turbo I had so the RPM may have played a part too but I think 350 is a good solid number for a street car to be at. If it's mostly a track car I would say very low 400s should be ok for stock bottom end but those engine are also getting torn down and checked more often than a street car, so if parts are getting stressed hopefully it's caught before there's a window in the side of the block.

I’ve just always wondered just how much more 6 bolt rods could take than 7 bolt and I’ve seen the 7 bolt rods pushed but not to the length of time I’ve seen 6 bolt rods beaten on, just been a curiosity of mine for some time. My stock 6 bolt rods seen about 20k miles making from 420 to 454 depending what set up I was on, and neither the stock rods or the non turbo pistons on them were the failure point in my case. With that being said though I’ve seen many cases like mine of 6 bolt rods being pushed for that kind of longevity, seen plenty of guys throw a lot of power at the 7 bolt rods (especially in the evo world) but stories of longevity are definitely fewer it seems.

 

[97egl]

Yeah the 6 bolt rods are just so much bigger than the 7 bolts I can see why they will take more power. Pretty cool the power you are making on N/A pistons. I would have thought the top ring land would break with how much less "meat" is there on the N/A vs Turbo but these engines never cease to amaze me. Makes a nice possible option for 1g owners wanting to run higher compression but not mess with narrowing and honing the rod.

With more knowledge and money I probably could have made the engine last longer but I was young, stupid, and just wanted to go as fast as possible.

Wish I had just kept the car at the 350 and I would probably still have it but after breaking 2 transmissions and then blowing the engine I ended up selling it before leaving for college. Took a huge loss since the engine was only half back together and out of the car and these cars didn't go for anything back 12 years ago.

 

[slugsgomoo]

I think it's worth noting that a 1g 7 bolt head and a 1g 6 bolt head are the same, except for the larger exhaust manifold studs for the outer two, and IIRC the head bolt holes are smaller. That said, the value in a "7 bolt" head only exists when it's a 2g head and not a 1g; otherwise, it's the same lousy large port design.

I'm in the camp following the Curt Brown way that says that if you're shooting for <800 AWHP, stick with a 2g head and benefit from the better angle on valves, better velocity, and more mid-range. I will admit that I'm fully committed as I've got a high compression 6 bolt 2.4 now and I'm still committed to the 2g head as it's more fun.

 

[VT_4G63]

Thank you everyone for the above replies and opinions. I found a lot of useful information here.

I believe I will be going with a full 2G 7-bolt long block, Evo 3 intake manifold, and I’m going to try and hunt down an Evo 3 exhaust manifold.

I’m going to keep my 6-bolt motors waiting in the wings, though.

Thanks again

 

[randman2011]

I’m going to try and hunt down an Evo 3 exhaust manifold.

I just saw one for sale for $100 on the Facebook group. I would link but Facebook is hot garbage and I couldn't find the post even if I know who posted it and exactly when.