Recommended Heads

[rnocobra]

Decided to replace the heads on my 351w based 427 stroker. I am really looking for some advice as to what the best all around heads available for a small block Ford. Any thoughts?

Thanks all!

[JayBar]

AFR 205's or maybe 215's

[Mister]

I think we could be more helpful if we knew more about your engine and your uses for it.

Mike

[rnocobra]

My current engine has been used primarily for street with an occasional visit to the track. I have heard that both the AFR and the RHS heads seem to be a great head for both street and track.

[Roscoe]

AFR by far......and I know from where I speak......

????
Roscoe

[RICK LAKE]

rnocobra You need to match the parts of your motor for what you want. If you are running a small cam shaft, those big 215 heads are not going to do much for your power output. The same applies to the intake, camshaft and the big thing the EXHAUST. This is the biggest power kill of some cobras. The best thing is to match the rpm range for all 4 parts. You are running a stroker 427, so you are looking for bigger flow heads. You also need a camshaft that has the lift and duration to match your power band. What is the max rpm you are turning?? Are you running a carb or FI system? What intake are you running and is it fully ported?? Are the runners match flowed? We need some more info before giving you what might be the best heads for your motor. Compression is anotherthing we need. Send a spec list on the motor and what you want the motor to do and in what RPM range, and we will try and give you the best bang for the buck. I have seen more people buy great parts and the motors run worse than stock motors. This is why intake manifold, camshafts, heads, exhaust systems, carbs have specs and rpm ranges for the most power output. Rick L.

[767Jockey]

How about a set of canted valve CHI 3V Cleveland heads? If you're going to switch heads, you might as well go for the gold standard.

[Keithc8]

The CHI heads will cause all sorts of things to be changed from headers to push rods, head bolts, intake manifold, rockers, valve covers, water routing out the front of the head. Not a very easy switch. The best choice is either the Brodix CNC track one that we do or the AFR 205 head that we do. We match the valve job and parts to what you are going to do with the engine as well as the parts used. We only buy the castings from the companies and do our own CNC porting. The 427 C.I. engine can use a pretty good size head and the camshaft would have a lot to do with what you need. Good luck, Keith

[hound dog]

I have a question. Why do people recommend approaching the selection of heads for a 427 small block with so much caution? Most of them do not approach the average big block flow numbers but yet we worry about getting too much air flow. Why? 427 cubic inches is 427 cubic inches whether it's in a small block or big block doesn't matter. I'd get all I can get! You won't come near the flow numbers of the heads made for the high performance big block 427's.
h dog

Just stirring the puddin'

[JAC]

Hey Keith, What about Ford Racing's CNC Z304 Heads? Are they any good? Looks like they flow pretty good numbers.
Just a thought.

[rnocobra]

I guess that is really the best question: why would the AFR 215s be too much for a small block 427?

[hound dog]

Really, I wasn't trying to start a fight or anything, just a discussion about airflow. From the AFR website, the minimum flow head for the big block Chevy flows 321 cfm at .500 lift through the intake valve. The max flow for a small block Ford is 289 cfm at .500 lift. Not even close to the same. I fully understand why you can't get more flow in the small block head, but I can't quite fathom why people recommend smaller head flow numbers for a 427 small block. Just thought about some of the recommendations going around on the web ref. small block/high cube engines and wanted to throw it out for discussion.
h dog

[vector1]

just wanting to replace heads, afr is the standard for the 23* jobs, but you need to talk to someone like kc and match everything, what is your compression, cam specs, carb, intake, useage. prob end up with 205's, unless you do 1/4 mile stuff then 225's might suit you better, although streetwise would prob suck. you need smaller ports to keep air/fuel velocity up to fill the cylinders at lower rpms and provide vacuum for your carb although this is a function of cam specs also. afr website has listing of lots of combos and a shootout of different heads and output at the bottom although prob biased. you could go to engine builder websites and see what they are putting on their strokers, give you a good indication. hth

[Bxx1]

I really like these threads, I could read these informed engine discussions all day. Great questions and thoughtful answers.

[RICK LAKE]

Hound Dog there are some good articles about basic heads, flow numbers, camshafts, weather swirl is better than straight shot into the cylinder. The importants of velocity of the A/F mixture. It comes back to the biggest head is not always the best head. It just means that with the right carb, camshaft, piston design, exhaust system, you can get the most power at a certain RPM range. Big head suffer in the 100-300" lift range and make it up in the 300-700+" lift range on the cam. I am not a pro, but have seen enough motor put togeather with the best parts and the motor runs like a pig. Again you can't compare a Ford head to a SBC head. I good motor to pick on is the Boss 302 from 1970. A pig from idle to 3,000 rpms, after that to 7,200 rpms hauling a$$. Why, Big ports. We are talking about stock motors from the factories. 302 Chevy was about the same. The rough ideal proportions are about 50-54% on the intake side and 38-42% on the exhaust for almost any motor. This is the valve size in respect to the cylinder bore size. You are hoping for an 84-94% VE ratio of the motor running. In the 90's is a solid strong motor maken great power and use of the A/F mixture. There is alot more than just this but I think you get the idea. I am not a pro builder. I do know that parts are made for certain applications. Matching the motor rpm range for power is the most important thing. I like torque motors over HP motors. Torque is what moves the car, HP is a by product in the upper rpms. It's a balancing act. Rick L.

[hound dog]

Rick,
I feel like I'm stealing rnocobra's thread here, but it has always been a burning question in my mind about the sizing of heads for the small block/large cube engines. As I stated before the biggest small block heads aren't near the same flow as the smallest big block heads. You can't get the big numbers because of the valve size restrictions. So, does that mean that we're not getting the full advantage of 427 cubic inches when we punch out the small blocks? I'd think that a 427 big block would out perform a 427 small block simply because of it's ability to put more fuel/air mix through the cylinders (all other things being the same). I'm no expert here either, but I'd sure like to here an explanation from some one who has experimented under lab conditions. I remember when I built the engine for my Unique a friend was pushing me to build the combustion chamber/piston according to a design by Endyne. This would give me a compression ratio of 11.7/1. I didn't think it would work but I did it anyway and guess what? It runs great on 93 octane pump gas! The things I don't know would fill an encyclopedia!
h dog

[rnocobra]

Steal away H-Dog - These are many of the same questions I have. Does anyone have any further thoughts?

[767Jockey]

Hence, my remarks on the Australian Cleveland heads. They're really canted valve big block heads on a small block, perfectly feeding those 427 small block cubes with a big block style head. Nothing makes the power these things can make on a stroker Windsor - not even close.

Look at the engine masters competition - the vast majority of stroker small block Fords entered are running the Aussie aluminum Cleveland heads. Look at Roush, look at Billy Mitchell, look at almost any engine builder. Their top of the line, highest output stroker Windsors are all Clevors - Windsors with Cleveland heads. There is a reason why. It's a big block head on a big block sized engine. Sure it's a bit more inconvenient - you have to buy a new intake and adapt the headers - so what. By the way, tell them you're putting the heads on a Windsor block when you purchase them and the heads will arrive all set up regarding the water passages - no big deal at all. You want massive power, or you want convenience?

[Keithc8]

When dealing in the real world most people are concerned about price and what it will take to make the headers and sidepipes that come with the car work. If they are wanting to build the baddest all out engine based on a 351 Winsdor engine the CHI heads as well as the Blue Thunder 4.30 or the Ford racing D3 are all options but not real pratical for a street engine. Most all of the engines on the Engine Master compition would not make it 1000 miles juch less 10,000 miles because of the light parts, low tension rings, compression and ever other little HP robbing trick there is to do. They are not real word street engines that you would put in a Cobra.
The reason for the bigger heads on the 427 Chevy is the basic design of the engine with a 4.250 bore which will accept larger valves easier and it has a large runner volume. These were designed to ne race engines and not street engines. If you look at the 454 street engines, they had a oval port small valve head for torque with a smaller runner volume. Just depends on where and how you want to make the power. I see this problem a lot with guys that have jet boats and install big heads and camshaft with a tunnel ram intake and it runs like crap. The jet will only let the engine go up to about 5000 rpms and they have way to much head, camshaft and intake. I have taken these guys and made all of this stuff smaller and they have ran much better in the boat.
If we were not dealing with street engines and could run the compression up to 14 to 1 and turn the engine to 8000 all the time the bigger heads would work great. There is a place for all of the heads on the market when used in the right application. Good luck, Keith Craft

[hound dog]

Keith,
Do you know what the flow numbers are for some of the 427 FE heads? I don't, just curious what they are.
h dog