Shopping for cylinder heads... questions...

SadbutTrue · Feb 9, 2008

Alright, finally gonna start looking for some heads for my 351 for a few months down the road. Based on previous research, I've heard that heads like the AFR 165 or 185 (probably 185), Trick Flow Twisted Wedge, and Performer RPM would be suitable for my 351 (which will have my current exhaust, a weiand stealth, 650 double pumper, hotter cam, etc on it).

I don't want to mess with my rotating assembly... ie no flycutting pistons and the like. I want the heads to bolt on and go. I believe I have a 72 351w... could be anywhere from a 69 to a 74, pretty sure its a 72 though.

What specific models of these heads can I use?

I'm pretty sure the Trick Flow heads are okay with 2.02/1.60" valves with stock pistons. I'm pretty sure Performer RPMs are not, and I can only run 1.9" intake with them. What about AFRs? What cc combustion chamber should I run? What else should I consider?

Thanks

bnickel · Feb 9, 2008

i'd go with a 60cc chamber or 58 if you can find one, and no bigger than 1.90/1.60 valves unless you go with the TFS TW heads. stock chamber size for your 72 (?) 351w is 60cc so to get the same compression ratio you'll need the 60cc heads but the 58cc heads will give you a small boost in compression. really though you need to consider at least replacing the pistons if nothing else in the short block because even with the 58cc heads you're only going to be making around 9:1 compression and you really need more like 10:1 with the aluminum heads to get the most out of the heads. just get some cheap speed pro hypereutectic pistons, cast rings and maybe new bearings and seals while you're in there. you don't have to worry about boring the block if you don't want to but i'd at least run a hone through it.

i've got a 73 351w with a speed pro cam and the stock heads and i could use another 1/2 point of compression myself.

SadbutTrue · Feb 9, 2008

bnickel said:
i'd go with a 60cc chamber or 58 if you can find one, and no bigger than 1.90/1.60 valves unless you go with the TFS TW heads. stock chamber size for your 72 (?) 351w is 60cc so to get the same compression ratio you'll need the 60cc heads but the 58cc heads will give you a small boost in compression. really though you need to consider at least replacing the pistons if nothing else in the short block because even with the 58cc heads you're only going to be making around 9:1 compression and you really need more like 10:1 with the aluminum heads to get the most out of the heads. just get some cheap speed pro hypereutectic pistons, cast rings and maybe new bearings and seals while you're in there. you don't have to worry about boring the block if you don't want to but i'd at least run a hone through it.

i've got a 73 351w with a speed pro cam and the stock heads and i could use another 1/2 point of compression myself.

Compression on the 72s that low? Ugh. Stupid smogger engines...

How much extra work is it to put some decent replacement pistons in (i'll need some suggestions for pistons capable of handling 450 hp... not that I expect that much but I don't want to be digging back in there any time soon)? We were trying to avoid pulling the engine (the more space and time required, the tougher it is to convince my dad to do it) but its probably a good idea.

SadbutTrue · Feb 9, 2008

bnickel said:
i'd go with a 60cc chamber or 58 if you can find one, and no bigger than 1.90/1.60 valves unless you go with the TFS TW heads. stock chamber size for your 72 (?) 351w is 60cc so to get the same compression ratio you'll need the 60cc heads but the 58cc heads will give you a small boost in compression. really though you need to consider at least replacing the pistons if nothing else in the short block because even with the 58cc heads you're only going to be making around 9:1 compression and you really need more like 10:1 with the aluminum heads to get the most out of the heads. just get some cheap speed pro hypereutectic pistons, cast rings and maybe new bearings and seals while you're in there. you don't have to worry about boring the block if you don't want to but i'd at least run a hone through it.

i've got a 73 351w with a speed pro cam and the stock heads and i could use another 1/2 point of compression myself.

And if I'm gonna get new pistons, I might as well get them notched for AFR heads. Are there any pistons out there than can take a pounding, provide 9.5 to 10:1 compression ratio, and come from the factory notched properly for AFR heads?

65ShelbyClone · Feb 9, 2008

I personally wouldn't worry about digging into the engine just to boost compression, not until you're ready to rebuild the hole thing anyway. You can still make good power with compression in the high 8s. There should still be at least a 50hp gain from the extra flow alone. I can't guarantee you won't need to clearance the pistons, though.

68stang351 · Feb 9, 2008

I'm gonna keep up with this thread because I'm in the same boat right now. Hopefully I will have aluminum heads on my car by the end of this summer.

Has anyone used any of the piston notching tools to notch the pistons? I was thinking of getting the Performer RPM heads. The 1.90 and the 2.05's are the same price so I figured I might as well get the 2.05s and notch the pistons. I've read that the 1.9 rpms will work with stock pistons, but if I'm gonna spend that kind of money I may as well spend a little more to get the pistons notched and have the 2.05s.

bnickel · Feb 10, 2008

the problem is that the aluminum heads NEED more compression than an iron head to make power becuuse they dissipate heat so much faster, yes they'll make more power just from flow alone but not nearly to their potential.

the other option would be a set of iron heads like world products 180's (jr.s) and you'll still make good power with the stock pistons.

Shakin66 · Feb 10, 2008

Dart makes great ford heads also..

I just wanted to add my .02 on cylinder head selection. All of the aformentioned heads would be great but I have Darts Pro one heads which are available in several configuations, do youself a favor and at least check them out...Whichever you decide to go with make certain to check your piston to valve clearance, its easy to do and could save you a lot of work latter.
View attachment 331071

Brand: Dart
Product Line: Dart Pro 1 Aluminum Cylinder Heads
Part Type: Cylinder Heads
Part Number: DRT-13071123
Cylinder Head Style: Assembled
Cylinder Head Material: Aluminum
Cylinder Head Finish: Natural
Combustion Chamber Volume (cc): 62
CNC-Machined Combustion Chamber: Yes
Intake Runner Volume (cc): 210cc
Exhaust Runner Volume (cc): 76cc
CNC-Machined Intake Runner: Yes
CNC-Machined Exhaust Runner: Yes
Combustion Chamber Style: Heart
Intake Port Location: Standard
Exhaust Port Shape: Square
Exhaust Port Location: Standard
Intake Valves Included: Yes
Intake Valve Diameter (in): 2.050 in.
Exhaust Valves Included: Yes
Exhaust Valve Diameter (in): 1.600 in.
Valve Springs Included: Yes
Maximum Valve Lift (in): 0.690 in.
Outside Diameter of Outer Spring (in): 1.550 in.
Damper Spring Included: Yes
Number of Springs Per Valve: Dual
Retainers Included: Yes
Retainer Material: Steel
Locks Included: Yes
Lock Style: 10 degree
Valve Stem Seals Included: Yes
Valve Stem Seal Style: PC seal
Rocker Arm Studs Included: Yes
Rocker Arm Nut Thread Size: 7/16-20 in.
Rocker Arms Included: No
Rocker Arm Nuts Included: No
Guideplates Included: Yes
Guideplate Pushrod Size: 5/16 in.
Valve Cover Mounting Style: Perimeter bolt
Accessory Bolt Holes Drilled: Yes
Valve Guides Included: Yes
Valve Guide Material: Manganese bronze
Valve Seats Machined: Yes
Valve Seat Machine Style: 4-angle intake/3-angle exhaust
Valve Seat Material: Ductile iron
Steam Holes Drilled: No
Oiling Style: Through pushrod
Machined for O-Ring: No
Heat Crossover: No
Quantity: Sold individually.

Cylinder Head, Pro 1, Aluminum, Assembled, 62cc Chamber, 210cc Intake Runner, Ford, 289/302/351W, Each

D.Hearne · Feb 10, 2008

My .02: The comp ratio starting in 72 for the 351W;s was in the 8 to 1 range, not 9 to 1. If you have the stock pistons still. There was a definate piston change from 71 to 72. I have one of each piston,(in my piston collection) the 72 piston top is dished even more than the 71 was. (sorry can't do pics here) What cam do you have now? And piston to wall clearance is critical for hypereutectics, so I'd advise against doing a piston swap without boring if using them. Cast? yea, you could get away with it, forged too. But I wouldn't with hypers.

danny clemens · Feb 10, 2008

If you take the engine apart you might as well do the whole rebuild thing. It wouldn't cost you that much more. That is unless it's in great shape. If you don't get the heads with 2.02 valves you might be sorry later on. It's a lot of decisions but you'll be the one who has to make the final decision.

D.Hearne · Feb 10, 2008

I didn't go with 2.02 heads and I've never looked back.

danny clemens · Feb 10, 2008

D.Hearne said:
I didn't go with 2.02 heads and I've never looked back.

If D. Hearne says the smaller valves are OK I believe him.

bnickel · Feb 10, 2008

smaller valves will actually create more velocity in the ports than larger valves and won't be as prone to shrouding in most cases.

what D.hearne said is pretty much what i was trying to say about the compression. the 72-up pistons have the "reverse dome" dish that just sucks all the compression right of the motor. a change to flat tops will boost the compression and allow the aluminum heads to do their job more effectively. i don't exactly agree that a hyper piston won't work in a standard bore though. otherwise why would they even offer them in standard bore and not just overbore sizes?

also shakin66 recommendation of the dart pro 1 heads will make the compression even worse with the big 62cc chambers.

IMO, if you're dead set on using the AFR heads then you need to change pistons as well or use a cast iron head with the same or slightly smaller chambers to retain some of the heat from the combustion process in the heads.

D.Hearne · Feb 10, 2008

I don't know the reasoning on std bore replacements, maybe for a new block? But I do know that the piston to wall clearance is tighter for the hypers and with them being more brittle, I don't think I'd want em any looser than intended.

SadbutTrue · Feb 10, 2008

danny clemens said:
If D. Hearne says the smaller valves are OK I believe him.

fwiw Edelbrock told me the difference between their 2.02 and 1.90 Performer RPM heads was likely to be about 5 horsepower, 10 max. Valve size isn't a huge deal.

Just really regretting getting rid of that 69 351w a few years ago right about now.

truck90278 · Feb 10, 2008

In SadButTRUE's original post, he did not say what his use/driving is going to. Does impact what you do with the engine. If this engine is original and not been rebuilt and has significant mileage, although runs well, changing only pistons and new rings has some concerns. With a fairly high mileage engine, cylinder wall taper enters into the ability of the new rings to adequately seal/seat. Although many/or all of the responders are very knowledgeable, I would suggest talking directly to the manufacturers of the heads. With deep dished pistons, notiching the pistons (assuming original/mild cam). Putting new heads on tired pistons/rings can lead to it's own set of problems. Potential for blow-by on the rings.

57fairlane · Feb 10, 2008

take .030" off the twisted wedges, run a .029" cometic . . .

Shakin66 · Feb 10, 2008

bnickle, If you noticed in what I typed they offer those heads in many different CC.s and runner sizes.

coolblue65 · Feb 10, 2008

57fairlane said:
take .030" off the twisted wedges, run a .029" cometic . . .

I would have to agree, I ran the Trick Flows and was very happy, and I would have been more so if I would have shaved down the heads a bit to up the compression. They flow somewhere in the middle of the AFR 165's & 185's and you get the 2.02" valves and you can run stock flat top pistons without notching them.

SadbutTrue · Feb 10, 2008

57fairlane said:
take .030" off the twisted wedges, run a .029" cometic . . .

HOw much does that usually run? Whats a 'cometic'? Does shaving the heads down still allow you to run 2.02s? How much does that bump up the compression? I like the idea in concept...

Shopping for cylinder heads... questions...

SadbutTrue

bnickel

SadbutTrue

SadbutTrue

65ShelbyClone

68stang351

bnickel

Shakin66

D.Hearne

New Member

danny clemens

Member

D.Hearne

New Member

danny clemens

Member

bnickel

D.Hearne

New Member

SadbutTrue

truck90278

New Member

57fairlane

New Member

Shakin66

coolblue65

SadbutTrue

Similar threads

Shopping for cylinder heads... questions...

New Member

Member

New Member

Member

New Member

New Member

New Member

Similar threads

Privacy & Transparency

Privacy & Transparency