Help me choose the heads for my engine upgrade

9052 Views 51 Replies 13 Participants Last post by 6t9mach1, Mar 14, 2012

rangerdoc

Discussion Starter · Mar 2, 2012

I'm converting my 302 2v into a 4v. The engine has a newer, but very basic rebuild. The cam is super mild, almost stockish. I'm putting on this Weiand intake Holley Performance Products Street Warrior™ Intake Manifold 8124 and this Holley carb Holley Performance Products 570 CFM Four Barrel Carburetor - Aluminum 0-83570

Soooo...I have no idea which heads to get for it. I have a 2.5" exhaust and would like to eventually put on headers that will work with the Borgeson system. I need something that is bolt on and go.

No racing planned, just a good cruiser. Recommendations please?

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6t9mach1

· #41 · Mar 7, 2012

You are right about the TWs being unique, however you'd never port a stock head to what an AFR flows.

Agreed

IF the TW intake port is better by having more average flow and better flow down low, then i guess we have to look at the TW vs AFR exhaust on the same wavelength

-Avg flow is 148.7 to 142.5, with the nod to the AFR
-Peak flow is equal at 189 cfm
-However, at every point along the way up, the AFR beats the TW, in some places up to 8 cfm

I'll agree that the AFR exhaust port beats the TFS exhaust port, but not bad for a cast runner vs. a cnc'd runner, ehh

A little bowl blend and vuala.

I didnt say TWs were substandard but you claimed they were better quality components, so you tell me why better than the AFR?

Does AFR have a valve as good as a Ferrea valve? Are the rocker studs ARP? In the past they haven't been. I'd be interested if they have changed in the recent past. I wish that I could remember who made the locks and retainers for Trick Flow; I thought that Mike at TEA had told me Comp Cams but I can't substantiate that.

We both know that flow numbers are flow numbers and that they don't mean a whole lot without looking at a whole lot of other info. Why don't we just forget all this AFR vs. Twisted Wedge nonsense and just go with a set of High Ports, lol.

irate:

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rangerdoc

Discussion Starter · #42 · Mar 8, 2012

6t9mach1 said:
With a "stockish" cam you should not have a problem with the Twisted Wedge heads. Its starts getting really close at .520" lift and 224* of duration @.050".

That's what I was thinking as well. Based on my cam specs I shouldn't even be close. I'd like to get the TWs since they are a bit cheaper. I really don't plan on ever doing anything else to the engine once I make these upgrades so I guess I'll never see the full potential of either choice. For whatever reason, would there be a difference to the installation? The TW instruction say I have to drill 4 holes into the water jacket, not sure if the AFR heads require that. It seems like such a toss-up between the two.

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6t9mach1

· #43 · Mar 8, 2012

The TW instruction say I have to drill 4 holes into the water jacket, not sure if the AFR heads require that.

That is a new one on me. Where does it say you need to drill the holes? Do you have a link to the instructions?

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rangerdoc

Discussion Starter · #44 · Mar 8, 2012

http://static.trickflow.com/global/images/instructions/tfs-dp-4%2C5.pdf
That should take you to the instructions. Look on page 2, figure 2 under "prepping the block". It applies to 351 SVO or pre-1972 blocks.

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6t9mach1

· #45 · Mar 9, 2012

The instructions got me interested so I did a little research since I never did that to my 351w block. Apparently Ford never had the holes in 351w blocks and supposedly they no longer drill them in the new performance blocks. Here is a link about the subject; make your own conclusions, do your own research or ask your engine builder. http://forums.vintage-mustang.com/vintage-mustang-forum/612654-help-drilling-steam-holes.html

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rangerdoc

Discussion Starter · #46 · Mar 11, 2012

Yeah, hard to draw a solid conclusion about that. I couldn't find any info about it on the AFR website either. Obviously, it doesn't seem to be critical since so many have never done it and have had no problems.

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rangerdoc

Discussion Starter · #47 · Mar 13, 2012

I asked Trick Flow about drilling the holes and this is the answer, "The purpose for drilling the holes is to allow the water to move around the cylinders to keep the cylinders cooler." Which doesn't help much concerning the other thread!

Man, I just can't decide. I'm leaning towards the AFR heads just because I know they will fit without any chance of issues. I'm fairly certain the TW heads would fit as well, but I just don't want to risk it.

For someone who has never done this, any advice for installation?

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6t9mach1

· #48 · Mar 13, 2012

rangerdoc said:
I asked Trick Flow about drilling the holes and this is the answer, "The purpose for drilling the holes is to allow the water to move around the cylinders to keep the cylinders cooler." Which doesn't help much concerning the other thread!

Man, I just can't decide. I'm leaning towards the AFR heads just because I know they will fit without any chance of issues. I'm fairly certain the TW heads would fit as well, but I just don't want to risk it.

For someone who has never done this, any advice for installation?

The AFR heads will be a fine head.

Advice...

1) make sure everything is super clean
2) make sure you install the head gaskets in the correct direction (yes you can install them the wrong way, just follow the directions and ask questions)
3) use ARP cylinder head bolts
4) use ARP's moly lube and use a torque wrench to torque the heads down in the pattern and sequence the directions say
5) buy a quality, adjustable roller rocker and MEASURE your pushrod length with a length checking pushrod. When ordering pushrods buy hardened pushrods. Trickflow makes a very nice, affordable hardened pushrod.
6) check piston to valve clearance with clay during mock-up and measure your clearance. You need a minimum of .080" of clearance on the intake and .100" on the exhaust.
7) make sure your cylinder heads have valve springs that are within spec for your cam. Using the correct valve spring is one of the most important things to take into consideration when installing a cylinder head.
8) did I mention to make sure everything is super clean?

Just ask questions along the way if you get stumped. It would be a good idea to measure how far down in the hole your pistons are before you buy head gaskets. This way you can set up the proper quench distance. .040"-.045" is a good distance between the top of the piston and the bottom of the cylinder head for sbf's. You can play with chamber cutout sizes to fine tune your compression ratio a little bit if need be as well. Stay away from copper gaskets, they are a real pain to get sealed and keep them sealed.

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rangerdoc

Discussion Starter · #49 · Mar 13, 2012 (Edited)

I appreciate the advice. I have several threads saved for installing the heads and intake, but not a consolidated list. I'll have to dig up my "rebuilding a small block ford" book as well.

Can you suggest good rockers to go with and the ratio as well? Could you go into detail how to use the clay? I'm assuming I need a piston to be at TDC. Is measuring one piston for clearance good enough or do I need to check all?

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6t9mach1

· #50 · Mar 13, 2012

A 1.6 ratio is the standard sbf ratio. That would be fine for what you are doing. As far as roller rocker brands I like Comp Cams, Crane and Scorpion Performance. A good, economical full roller rocker is the Comp Cams High Energy rocker (aluminum) or the Comp Cams Pro Magnum roller rockers (chromoly steel). These go for around $170 a set. I've ran the High Energy rockers before and they were fine. For a little bit more money you can get a great set of roller rockers for the money in the Scorpion Performance rockers. I have these on my current build and they are very, very nice! These go for around $220. Any of these rockers will do. When buying heads I always like to go with the larger 7/16" rocker studs since they will flex a little less if you ever decided to swap out camshafts and go with one that requires a stiffer valve spring. Whatever size you get (3/8" or 7/16") just make sure you get the right sized roller rockers to match.

As far as using clay goes its really simple. Just put some clay in the valve reliefs of the piston, even with the top of the piston. Bolt the head on and rotate the engine over (slowly as to not damage the valves). Pull the head and check the clay. If there are no marks on the clay then the valve has plenty of clearance. If there is a mark in the clay carefully pull the clay out, cut the imprint in half and measure the clay with a caliper. This will tell you what your clearance is. If you have plenty of clearance with one you should be good to go with the other cylinders.

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rangerdoc

Discussion Starter · #51 · Mar 14, 2012

Thanks so much for the continued advice. Is there a way to determine which length push rods to buy without having the engine apart? Should I just get the adjustable ones so I don't have to worry about it? I'm attempting to not have the engine apart for too long.

The AFR heads show a 3/8" stud size, so I'm assuming I'm limited to those?

Looks like I need to start assembling a parts list. Once I do, I'll post back with what I found to see if I'm missing anything.

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6t9mach1

· #52 · Mar 14, 2012

rangerdoc said:
Thanks so much for the continued advice. Is there a way to determine which length push rods to buy without having the engine apart? Should I just get the adjustable ones so I don't have to worry about it? I'm attempting to not have the engine apart for too long.

The AFR heads show a 3/8" stud size, so I'm assuming I'm limited to those?.

No way of knowing pushrod length without measuring, there are just too many variables. The adjustable pushrods are just for measuring purposes so you dont have to buy different lengths of pushrods.

In the optional equipment and parts section down lower in the web site it says you can get 7/16" studs. I'd call up AFR and see if they use ARP rocker studs. If not then I would swap out the studs on the head for ARP hardware. Probably not needed for your application but rocker studs are a bad place to skimp on and they are not that expensive.

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