Help me build my motor.

addicted · Aug 17, 2012

Just finished paying off my Dodge diesel DD so its time to get serious on my Bronco build. Its going to be a simple, strong, and dependable build. 3.5 SL, 2" BL, 35" tires. NP 435, twin sticked D20 with HD output, 31 splined Tru Trac rear. Fullsize disk braked D44 with a Detroit Soft locker. 4.11 gears. 4x4x2 box. Chebby TREs.
Now for the motor. I have a bunch of engine parts from a 79 F100 project I sold. I would like to use as much of them as possible. Heres what I have. 71 351W block bored 30 over. Scat cast crank. Eagle SIR rods, Miloden high flow water pump, Speed Pro forged pistons, Edelbrock 650 AVS Offroad carb, DUI dizzy, and other odds and ends. My goal is a 9:1 CR, torquey motor for highway and mild to moderate offroading. I figure the torque from the 351W will push 35s and 4.11 gearing well enough to cruise on the highway without over-reving the motor and still have decent get up out of the hole.
So I need opinions on cam, heads, and intake manifold. Based on what I have already and my plans and goals for the build. I know alot of you are going to say to go EFI and Edelbrocks are junk and so on, but its what I have and its simple and thats what Im going with for now. So heads, cam, and manifold advice please. Thanks.

bad 68 · Aug 17, 2012

If you want to use the pistons you have that may determine what cc heads you can use. You will need to know the valve relief cut cc of the pistons to determine combustion chamber volume, or buy the heads you want and get correct pistons.

With heads it all comes down to budget. If you want to spend $350 you can get GT40 iron heads used ready to bolt on. If you have $1200 you can get brand new aluminum heads from several different manufacturers ready to bolt on.

As for cam your going to get a lot of differing opinions. The bigger the motor the more aggressive cam you can run. 224 degrees @.5 on a 302 would be quite race where in a 351 it is quite off road-able. With a roller cam you can get lift without a lot of duration, with a flat tappet the two go hand in hand.

As for manifold I believe the Wieand stealth is the way to go. Your going to need a hood with a scoop but it should fit with the 2inch bl. Otherwise edlebrock performer is a good low to mid rpm manifold. The wieand is about 2 inches taller than the edelbrock and offers good low, mid and High rpms.

broncnaz · Aug 17, 2012

Heads best you can afford. Wouldnt even look at any stock heads they are all to small for a 351.
Camshaft needs to be matched to the gearing and driving needs I'd say something like the performer or close to it. I like crane cams I like there H272 for a 351 should give all around good power.
Intakes I kinda like the edelbrocks here I'm also more partial to the RPM style they may be a little taller but they make the power. but Im sure the wieands are just as good.

addicted · Aug 17, 2012

Thanks guys. Im already thinking that the pistons I have are not going to be used. Reason being is that they will produce 9:1 (minimum depending on head gasket thickness) with 64cc heads and most of the performance heads Ive been looking at are 58-60cc. So now Im looking at some dished KB hypers to go with some AFR or Trick Flow heads. Just not sure would valve sizes would be a good choice. Im not going to mess around with iron heads. For the intake I was thinking about an Edelbrock Performer RPM but I was also considering the Stealth. Im not too worried about underhood clearance as I'll be running a 2" body lift. If it becomes an issue I'll just get a different hood. At this point Im starting to think the only bottom end parts I'll be using for sure is the crank and rods because Im considering picking up a roller block. I like the idea of a one piece rear seal and running a roller cam. And I guess if I do that then Im going to have to switch out the gear on the dizzy. This might get expensive. lol

broncnaz · Aug 17, 2012

You can usually run a little more compression with aluminum heads like 1-2 points more without issue. really you wont see a big jump in compression between 64cc and 60 cc heads usually less than maybe 1/2 a point or so. What P/N are the pistons?ve got some specs on some speed pros.
I've had good luck with the TFS heads one thing I'd say is you dont need the best flowing head out there AFR's are kind of a waste of money IMO unless your racing or just have a big stroker.
Roller blocks are nice but since you have most of what you need now for the current block I'd go with that.
I wish I could find the dyno article on the performer vs the RPM but it was suprising to see that the RPM beat the performer at low RPM as well as high RPM. Im happy with the RPM on my 302 with TFS heads. I went with TFS heads on a 302 because at the time they were one of the only options availible they were a good price and i figured i would go with a 351 one day will 15 years later that 302 is still running fine.

addicted · Aug 18, 2012

Im offshore working but I'll check the part# on the pistons when I get home. I "think" these are the ones I have http://www.summitracing.com/parts/SLP-L2446F30/ I originally bought forged pistons because I was planning on spraying the motor for the other project and now Im wondering if I even need them. And Ive heard people say you'll get piston slap on start up with forged. Any truth to that? For heads Im leaning towards 185s. Ultimately I want a low RPM motor that wont completely fall on its face if I do run it past 4500.

addicted · Aug 18, 2012

I appreciate the advice. Ive already wasted alot of money listening to "hype"and now Im just as confused as when I started. The Scat crank I have can be used with both one piece and two piece rear seals. The rods are standard length press fits. If you dont think there is much of an advantage to going with a roller block then I'll stick with what I have.

broncnaz · Aug 18, 2012

Here's the specs I got for the 2446's 9.03 with a 63cc head and 9.26 with a 60 cc head. of course the 71 block you have should have the shorter deck height so you would probably pull closer to 9.6 with a 60 cc head. Drop down to 58 cc and your probably at 10-1.
Forged pistons do tend to slap a little until warmed up basically you shouldnt just start the engine a zoom off as extra wear can occur but then again thats kinda true with any piston. Just that forged pistons will tend to make a little noise until they are warmed up after that they are considered to be able to take a lot of abuse.
The heads are up to you 185s will be fine Like I said I run TFS heads on a 302 lowend is great top end is better, it doesnt fall on its face with the big valves. So a 351 will be fine. personally for the price I dont think you can beat the other brands as AFR's usually run close to $500 more than anything else. I dont see the small amount of power they may make being worth it. if you were racing maybe on a bronco no. but it is what it is buy the ones you want and be happy they will be fine. Also keep in mind that better flowing heads tend to move the power band up in the RPM range.
Nothing wrong with roller blocks just no big advantage IMO. yes roller cams are nice and less change of failure. But have a more limited choice of camshafts that tned to cost more than flat tappet cams. If you were racing then yes the roller cam has more of a advantage with less friction and quicker lift rates. 1 piece seal can be nice but if it fails you have to remove the tranny or engine to replace where the 2 piece you can just pull the oil pan.

addicted · Aug 18, 2012

Thanks for the help. I was checking out TFS heads and it looks like my options are some 170s that are 61cc and the 185s that are 64cc. The 185s are 400 bucks more and still alot cheaper than AFRs. Based on what my plans are, which of those two would you choose? I want to pick a good set of heads and then decide if I need new pistons or not.

addicted · Aug 18, 2012

Im thinking these. And I can use my pistons and still keep my CR down
http://www.summitracing.com/parts/TFS-51406404-C01/

Godwick · Aug 18, 2012

I've been thinking about a similar build for a while now - subscribed! Question, though: how does one know if one needs hypereutectic pistons or forged or simply OEM? We're not running high comp ratios or blowing the motor, so I'm thinking that OEM would prob get the job done, no?

bad 68 · Aug 18, 2012

I have seen they dyno results of rpm vs performer and I would go with either the rpm or the stealth but both are about 2" taller than a performer. with the tall deck height of the 351 you will need a new hood and the 2 inch BL and a drop base air filter housing.

As for cam I would spend the money and go with a roller setup, but thats me. Im not loaded but I'm not a broke ass either. You can get a .500 max lift roller cam with only 214 degrees duration. You can't get those numbers with a flat tappet.

addicted · Aug 18, 2012

Godwick said:
I've been thinking about a similar build for a while now - subscribed! Question, though: how does one know if one needs hypereutectic pistons or forged or simply OEM? We're not running high comp ratios or blowing the motor, so I'm thinking that OEM would prob get the job done, no?

I think if you are doing a stock rebuild then cast pistons are fine. If you are building for performance then I would step up to hypers. And for blowers, turbos, and nitrous you definitly want forged. I originally bought the forged pistons for a different project.

addicted · Aug 18, 2012

bad 68 said:
I have seen they dyno results of rpm vs performer and I would go with either the rpm or the stealth but both are about 2" taller than a performer. with the tall deck height of the 351 you will need a new hood and the 2 inch BL and a drop base air filter housing.

As for cam I would spend the money and go with a roller setup, but thats me. Im not loaded but I'm not a broke ass either. You can get a .500 max lift roller cam with only 214 degrees duration. You can't get those numbers with a flat tappet.

Yea. I havent completely made up my mind on the roller set up yet. I already have the 71 block and Im not sure I'll see the benefits of a roller cam in my build plan. But who knows. My block was machined a long time ago and has been sitting on a stand for 4 years. I need to take a good look at it and possibly have it recleaned and inspected and go from there.
Im most likely going with the Performer RPM for a manifold.

broncnaz · Aug 19, 2012

addicted said:
Im thinking these. And I can use my pistons and still keep my CR down
http://www.summitracing.com/parts/TFS-51406404-C01/

Should be fine with that setup I really wouldnt worry much I dont think Compression is going to be a issue. 61cc heads give only around 9.5-1 and aluminum heads can usually run about 1-2 points more compression than iron heads so you should be able to run pump gas just fine.
Basically the build is goinf to be pretty mild so the best flowing heads are not really needed even the base 170 heads will be more than enough for a 351. If you were looking to pull every last bit of power out of the engine so you could run down the track then the bigger more expensive heads would be what you want but for what your doing they are not needed. IMO

73azbronco · Aug 19, 2012

go with the smaller heads (165-170), you'll improve torque.

addicted · Aug 19, 2012

So you guys are thinking the 170 TFS heads would be a good choice?

broncnaz · Aug 19, 2012

I think they are a good choice. For the money your getting all you need on a 351. heck why spend $4-500 more dollars on bigger heads that are really not going to give you anymore power unless your pulling 6000+ RPM. Even then your probably only looking at a couple HP differance.

addicted · Aug 20, 2012

Ok cool. Thanks. Im really trying not to get caught up in the "bigger is better" mind frame. I dont "plan" on running it to 6K. Didnt plan on spinning the 460 in my 79 up that high either though and yet somehow it found its way there a few times. lol. So with your guy's advice Im going with TFS 170s, a Performer RPM and,.......... a 100 shot of a nitrous. JK ;D

Help me build my motor.

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