I have a 351 roller block and gt40 tubular intake. Thinking about stock 5.0 cam and 1.72 rocker arms and AFR 165 heads. Are the AFR 165 heads designed to operate in a higher rpm band then my intake? I have a 75mm bbk tb left over from a turbo 302 but think may be too big for this setup.
Are AFR 165 too much for gt40 intake?
- Thread starter enyawix
- Start date
Shaolin Crane
Banned
I think the cam is the biggest mismatch. The heads are a little small, and will limit the potential of the engine, and ditto for the intake. If you're not after peak HP, and want lots of torque, they heads and intake could work, though I would go bigger on both. The cam needs upsized in my opinion. The 75mm TB is about right for a 351 with "normal" sized components. I'm running an 80mm on my 369.
the 351 Lightining lower flows a ton compared to the 5.0 version, but the upper will choke it some on a 351. The intake will flow very close to the peak head flow as-is.
You are correct about me wanting lots of torque. I am basing my build on the 1995 Cobra R. Thinking my build could be better because the spec sheet I found said 300 HP @ 4800 RPM 365 lb-ft of Torque @ 3750 RPM. gt40 heads, gt40 intake, hydraulic flat tappet cam, and 1.7 rocker arms.
Wondering if the stock 5.0 cam and AFR heads would be am improvement on the Cobra R setup with out hurting Tq? I think the 5.0 made like 215hp and 300 Tq?
I say do it. The 165's are small-ish...if you're trying to make 500 HP, but they'll easily support 400 even on a 5.8/351w. The 5.0 cam however...isn't going to cut it. It would be adviseable to email someone such as Ed Curtis. Tell 'em what you want as far as idle quality, etc...and those guys will get you what you're looking for.
The AFR 165 heads would be a step up from GT40 heads, but you could up the size of the cam significantly without hurting the torque output. Increase the lift to roughly 0.500, and the duration to 215 at 0.050 wouldn't hurt your torque, but would pick up some power. In the end, the 165 heads and GT40 intake will limit what you can get out of it. For a 351, I don't see a down side to using the 185's versus the 165's for what you want, and would add more flexibility for later if you chose.
I have a tmoss modified Explorer 302 intake, and wanted to ask about the same question about my dream 347 and my current 302.
What AFR size head do I need for the Explorer intake for my bench racing 347 (close enough to same I figure) or my 302? I also want some low end torque for on the street on the 302 Are 185's too much for the street/strip 302? Do they make different models for 5.0 roller vs older 302?
If I want to go with the other company, which size and model number TFS heads do I want for the 347 or 302? Both will be based on the 5.0 roller block.
Unless you have specific favorites, I'll ask the cam makers about the combo with a manual trans.
stepping from a 165 to a 185 will often result in better power, even when holding everything else essentially the same. To compensate for the intake, use a different cam with a little more duration/lift.
What cam do you think would work well? I would like to keep valve overlap to a minimum, because I may go with a turbo setup in the future.
I'm detecting a slight hint of the putrid smell of the big-parts-hurt-torque myth in this thread.
As you can see in my sig, I've got TW 205s on my 302. A TW 205 is supposedly the equivalent to a AFR 215-220 in terms of port cross section (yep, a TW 205 is a bigger head than an AFR 205).
My car does not suffer from any lack of torque.
Now, I'm not telling you to go put 205s on your car (it ain't cheap!). But, I'm using it as an example to demonstrate that AFR 185s are NOT too big for a 302. Not at all. Match the cam, intake, and exhaust properly, and a 185 headed 302 could potentially be a pretty badass little motor. There is, of course, the issue of piston to valve clearance with stock 302 pistons.
I would consider AFR 185s a bare, bare minimum for a 351. Enyawix, I think you would be doing nothing but limiting yourself with 165s on a 351.
As you can see in my sig, I've got TW 205s on my 302. A TW 205 is supposedly the equivalent to a AFR 215-220 in terms of port cross section (yep, a TW 205 is a bigger head than an AFR 205).
My car does not suffer from any lack of torque.
Now, I'm not telling you to go put 205s on your car (it ain't cheap!). But, I'm using it as an example to demonstrate that AFR 185s are NOT too big for a 302. Not at all. Match the cam, intake, and exhaust properly, and a 185 headed 302 could potentially be a pretty badass little motor. There is, of course, the issue of piston to valve clearance with stock 302 pistons.
I would consider AFR 185s a bare, bare minimum for a 351. Enyawix, I think you would be doing nothing but limiting yourself with 165s on a 351.
I am sure the 185s will out our flow the the gt40 intake by a wide margin. What cam would you select and how would you expect the dyno graph to differ from that of a 351 Cobra R?
I am sending my intake off for be polished like this one.
Do you offer that kind of work?
I feel like I am being pushed to build a totally different kind on engine than the 351 Cobra R. Something with BIG dyno numbers crazy idle and nothing on the bottom end.
I am sending my intake off for be polished like this one.
Do you offer that kind of work?
I feel like I am being pushed to build a totally different kind on engine than the 351 Cobra R. Something with BIG dyno numbers crazy idle and nothing on the bottom end.
Haha, I do look for it a little bit. I just like to blow that misconception out of the water, because, IMHO, it's an unnecessarily self-limiting mindset.
Not trying to push you at all. I just think you'll be disappointed with an AFR 165 headed 351. Starting with a bigger head (like the 185) is going to allow better performance up front, and also leave more room to grow down the road.
I'm also not promoting a nasty cam, which would lead to the crazy idle and soft bottom end. You should look into Comp's XE line, some of those milder ones will bring a lot better performance than a stock HO cam without sacrificing drivability or low RPM performance.
Or look into a custom cam if you're so inclined. Like Tom said, if you really want that engine to sing with the tubular upper on it, you're probably going to want to look into something with more duration, but that also usually comes with a tradeoff in low end/ drivability. That's where a custom cam grinder could come in really handy.
What is this engine for? Are you doing a Cobra clone?
I will see what tmoss says. if he says it will not hurt air velocity I will buy the 185s.
25thmustang
Mustang Master
88-378
Member
I agree with 25th.
I have a 331 with 165's and a Cobra intake. It's right where it needs to be. With a 351, the 185's are a must.
I have a 331 with 165's and a Cobra intake. It's right where it needs to be. With a 351, the 185's are a must.
Thanks for all the help
I found a 168 vs 185 dyno graph on google. The 185 made more torque across the power band. There engine was a 347. I hope the difference from 347 to 351 will not matter.
AFR 165 cc vs. AFR 185 cc
I found a 168 vs 185 dyno graph on google. The 185 made more torque across the power band. There engine was a 347. I hope the difference from 347 to 351 will not matter.
AFR 165 cc vs. AFR 185 cc
