AFR 165 or AFR 185s for 351 ?

[Zero_chance]

Well Ive been doing a lot of research lately since I bought the new short block and my first instinct was that the 185s were the choice for a 351. But Im on a website right now that has this listed.

General sizing guidelines:

AFR 165 Heads - Stock 302's - mild 331/347's - Torque 351 applications

AFR 185 Heads - Max effort 302's (piston notching required!), 331/347 strokers, 351's and torque 393-408 applications

AFR 205 Heads - High RPM or power adder 331-347 strokers, 351-427 strokers looking for great torque and efficiency

AFR 225 Heads - Max Effort 347-363's, High RPM 351-440 large cube strokers


So does that mean Id get more torque out of the 165s as opposed to the 185s? Im not realy looking for top end speed as Ive never been down the track and even if I did end up going, it would be for my own personal satisfaction. Not interested in being the fastest person around. Maybe someone with a little more experience on the matter could chime in. I like low end power for around town fun so dont need something thats only going to perform in the high RPM range.

 

[95BlueStallion]

I personally would go with 185's. I would feel like Im choking the engine a bit with 165's... If youre going to spend the money you might as well get the heads that will give you more potential for improvement later on without being replaced... My $.02

 

[Zero_chance]

That was my first thought as well, I just wanted to poll the audience. And its not like theres a big price difference between the 165s and 185s. Just didnt want something that was more suited for top end and high rpm.

 

[blksn955.o]

I would go 205 or those new comp 185's. Regular 185's would round out the top 3.

 

[1slow95]

What are your rwhp/rwtq goals? Stock bottom end?

I would go with the 185's or larger. You will need different pistons to clear the larger valves though. That's the case with 302's anyways, I would assume the 351 is the same.

 

[Zero_chance]

I looked at the 205s but they seemed more suited for a bigger cubed 351 stroker. Keep in mind, 99 percent of my driving is from home to one of my two jobs and back again. The other one percent is joy riding on the back roads around CT. I think if I end up stroking it to over 400 CI then Ill definitely be getting the 205s. My original plan was for the 427 stroker but the more I thought about it, the more I realized that its kind of overkill. Not saying I wont go there, or upgrade to that in the future, but in the meantime Im thinking a 351 will be a healthy upgrade over what I have now. Then when I get the urge for more, I can add a stroker kit.

As far as what I want for numbers, kind of hard to say. I have no set goals in mind. You set a goal and dont reach it, you get pissed. Dont set a goal and end up with nice numbers, youre pleased. My ultimate goal is to be able to smile every time I jump on the gas. I think the 351, 5 speed and 3.73 gears I have in my storage unit should be enough for that.... If only I ever had the time to work on the car....

 

[Zero_chance]

And I would likely be keeping the stock crank unless theres a reason not to that Im unaware of right now. Havent pulled it apart yet. Pistons and rods will be replaced an upgraded to forged components.

 

[95BlueStallion]

If you think you may end up stroking it later in life I would go ahead and get the 205's... They may not help produce quite the torque of the smaller heads, but I dont see the sense in buying two different pairs of heads within 5 years or whatever. Unless youre going to give the old pair to me that is...

 

[1slow95]

For a DD or a car that will driven frequently I don't see any reason for going overkill with a 400+ stroker. AFR 185's, mild cam, and Performer RPM or Trick Flow intake should be fun. I would guess somewhere in the 300-350rwhp range. I would go with a 9:1 to 9.5:1 CR so you can add some boost down the road if you get bored with it.

 

[Zero_chance]

Low5.0 is thinking along the same lines as me. The 427CI was a passing thought. Have to admit, it would be badass to have one under the hood. As for purpose, is there ever really a purpose for the things most of us do to our cars?

 

[Zero_chance]

And if I ever did go over 400 CI I have my Mountaineer for a daily driver. Eventually Im going to make that switch anyway as I want to keep the miles on the car low.

 

[Black95GTS]

AFR 185 Comps or AFR 205s for my .$02

Adam

 

[blksn955.o]

You may want to look into the budget 393 setups if your talking about wanting new rods and pistons. I would not spend the money on aftermarket rods...the block should still fail before they do even with a 351 depending on the block used. I would either just run a solid rebuilt 351 or a budget 393 if I was looking to do it as cheap as possible.

The factory rods are for what your talking about 100% fine. Get some ARP hardware and reuse them.

The budget 393 is a nodular crank, stock rods, and 302 pistons. You will probably find that stroker setup cheaper than aftermarket forged rods and pistons. I know the 302 had forged rods stock and think the 351 did as well...just get some good rod bolts and have them all machined together.

With the cubes 205's or comp 185's should not kill your trq. 185's fit with no mods to 351's a buddy of mine put some on his gen1 lightning and did nothing else. 205's may need more room that I do not know.

IMHO 165's are just too small for the cubes and with the comp 185's they should be a good fit between the reg. 185's and 205's.

 

[Zero_chance]

Not necessarily needing to go budget on everything, I dont mind spending the money if its one less thing that wont have to be worried about. Though Im a tech, Im still relatively new to performance build ups so I appreciate the input. If the stock rods are fine to be reused then Ill likely just reuse them with the ARP hardware and put the extra money into something else. Definitely still want forged pistons though. Pistons are subject to more abuse and I dont feel they should be skimped on.

 

[blksn955.o]

Forged pistons are a no brainer as far as getting forged or not IMHO. I have seen too many pics of KB hyper pistons to even want to go that route.



If your running a roller 351 block (94+) just keep in mind IIRC they let go at around the 600-650 mark. If your looking to spend money on forged cranks and way better rods that will hold say 1000hp. It is wasted money as the block will let go before that so why build it with parts that can handle that if you dont have to/cant?

A good nodular crank and stock rods with forged pistons should be able to handle about all a later casting 351 block can handle.

 

[Stopsign32v]

205s if you want to go fast.

 

[Zero_chance]

I agree with what youre saying blksn955.0, and if I did go the stroker route, I was looking into the kits that fordstrokers.com has. Ive hear nothing but rave reviews about them. Though if I stayed at 351CI Id likely just keep the crank as it is and upgrade the rod hardware like you suggested as well as get forged pistons.