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  #16 (permalink)  
Old 11-12-2018, 07:49 PM
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I couldn't ask for a more complete recipe than that. When I began the restoration of my MGA I found a forum for British cars that was made up of a bunch of really friendly and helpful guys willing to share anything they could with me. It was an enormous and enjoyable resource for me. This is the first "hot rod" build I've done since my '55 Chevy when I was 18 years old and I'm 70 now. When I began this Fairlane build I looked around for a website like I had for my MGA and this site is far and away the best one I've found. You guys are great and I can't tell you how much I appreciate all the feedback and advice you've given me. Thank you!

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Old 11-12-2018, 08:15 PM
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You're welcome, forgot to tell you, the pistons are Keith Black Hypereutectics.
Here's a tutorial for getting the correct pushrod length.....

Last edited by techinspector1; 11-12-2018 at 08:23 PM.
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Old 11-12-2018, 08:15 PM
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It's a good plan....I can't see a place I could improve it one bit.....any changes I'd make would just move the powerband higher up the RPM scale, and that's not what you are looking for.
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Old 11-12-2018, 11:14 PM
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Originally Posted by Molon Labe View Post
Thanks Bogie and thanks Eric,

I was going to ask about the GT-40 heads.

Joe
Not a good choice for a 351,first they were used on 302/5.0's that use a 7/16" head bolt and 351's use a 1/2" bolt so you would have to drill them out,second the GT40's have very weak valve springs with limited lift they would need to be replaced not a good "bang for the buck" to gain 20-30 HP.
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Old 11-13-2018, 07:57 PM
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GT40 and the better GT40P heads are better on the 302/5.0 engines they take a lot of work to make them suitable for 351's. Yes they can be built but it's more work and expense than they are worth in a world full of aftermarket heads.

The FloTecs that Tech suggest are a very excellent low cost way to pump up the Ford 351, another low cost option on these engines is the Pro Comp, moving up the price ladder is Skip White's NKB head, any of these buy a lot of bang for the buck. But you have to plan for aluminum heads up front because the block should be zero decked since aluminum heads need protection from the inevitable rubbing between then and the iron block and its lesser rates of thermal expansion. So typically this involves thicker multi-layer steel or graphite composition head gaskets instead of a thin shim gasket. So you have to cut down the block decks to get the optimal squish/quench clearance with the thicker gaskets. Heads should be bought without valves, springs, and other top end finishing parts. It is important that these match the cam grinders specs, and the valves meet the quality of the end use of the engine, not the concept of one or two 'sizes' fit all.

Those who warn that a regular T5 will not put up with this. The 8 inch is iffy but if you under size the rear tires you can by some space by using the tires as a torque safety valve.

Bogie
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Old 11-14-2018, 08:34 AM
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Bogie,

Thanks for the feedback. I checked out Skip White's site. His NKB heads are assembled at his shop in TN with Comp Cam parts. At $699 they're actually cheaper than the Flo-Tek heads too. They flow 214/160 at .400".

I've done some more searching and came across some articles on ProMaxx Heads (used to be Patriot). They have some impressive numbers and sell for $925. They flow 233/176 at /.400".

https://www.hotrod.com/articles/ccrp...head-shootout/
https://promaxxperformance.com/product/maxx-180-sbf/
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Old 11-14-2018, 09:47 AM
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LOL, once you see what's out there the 'greed for speed' takes over.

There are a lot of heads available in aluminum and iron, bare to complete.

The head test you sight is just a little bitty sample of this stuff that can range from a set of bare ProComps off eBay for 400 dollars to used but professionally prepped Darts for 5000 on Racing Junk! And a pile of stuff inbetween.

Some thoughts to take shopping with you about chamber efficiency and or flow values and their results on power. Where the cam and for the most part compression is held common as with the head test you linked you can begin to see the impact of chamber shape on power as a seperate issue from port flow.

A good data point is the Vortec head against the old standard, while the Vortec shows better power at lower RPMs this is mostly the effect of better combustion, you see this happening at lower RPM than the standard head which tells you that engine demand for flow was smaller yet torque and horsepower are larger values. This is the effect of what's called 'fast burn' it is also evidenced by a reduction in the rate of advance needed to obtain these better values and the fact that ramming old fashion extreme advance numbers into it causes a power loss at worst and nothing at best.

Since mostly everybody uses these chambers developed by Sir Harry Ricardo in England and Professor Charles Fayete Taylor in the USofA, these known as Magnum from Chrysler, GT40 at Ford, or Vortec and Fast Burn at GM; you can draw some comparisons between brands and models within brands. Edlebrock uses a simpler version of the chamber and typically sees a little lower set of values than the competition, the Flo Tec uses nearly a copy of the Vortec and for flow reasons sees lower outputs than the competition that are comparable to the iron Vortec. The ProComp has older versions that had simpler chambers similar to the Edelbrock but combined with a port that was lazy at lower lifts but flows like gang busters at high lifts. Those are mostly gone from the market replaced with a much better chamber but the same ports. The newer version like the preceding really works well with fast and high lifting cam's. Heads that have characteristics like these work best with modern cam's like the Comp XE series or the Lunati Voodoo series or with aftermarket roller cam's where short ramps, fast lift rates, and high total lift is the rule. So just looking at peak port flow isn't close to the whole story.

So this can be a complicated topic with potentially a lot of money on the line, what I sight are some simple things to look out for and consider as you open up the catalogs of head choices and your brain and eyes glaze over.

Bogie

Last edited by BogiesAnnex1; 11-14-2018 at 09:57 AM.
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  #23 (permalink)  
Old 11-15-2018, 07:10 AM
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Well, my eyes haven’t glazed over but they hurt from doing so much reading in the last few days. What I’m realizing is the need for knowledge becomes exponentially higher if you hope to extract every last bit of power from a build. I understand that a sub $1,000 set of heads are not going to manufactured with the same quality, or, perform equal to the top line products. But I’ve come to believe I can get a decent set of heads that will meet my requirements in that price range. I’ve looked closely at the NKB heads from Skip White, the Promaxx heads and the Flo-Tek heads. With no experience to base it on, some people advise against these heads for no other reason than being made from Chinese cores. However, feedback from folks that have actually run them is very positive.

I’m hoping to get the engine done over the winter while I finish the body, so, I don’t have to make a decision tomorrow. I’m going to take some time, re-read and digest all your comments, do a little more reading and make a decision. Right now the Promaxx heads are looking good – but that could change. Thanks again for everyone’s advice.
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Old 11-17-2018, 11:59 AM
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Well, my eyes havenít glazed over but they hurt from doing so much reading in the last few days. What Iím realizing is the need for knowledge becomes exponentially higher if you hope to extract every last bit of power from a build. I understand that a sub $1,000 set of heads are not going to manufactured with the same quality, or, perform equal to the top line products. But Iíve come to believe I can get a decent set of heads that will meet my requirements in that price range. Iíve looked closely at the NKB heads from Skip White, the Promaxx heads and the Flo-Tek heads. With no experience to base it on, some people advise against these heads for no other reason than being made from Chinese cores. However, feedback from folks that have actually run them is very positive.

Iím hoping to get the engine done over the winter while I finish the body, so, I donít have to make a decision tomorrow. Iím going to take some time, re-read and digest all your comments, do a little more reading and make a decision. Right now the Promaxx heads are looking good Ė but that could change. Thanks again for everyoneís advice.
Costco has good prices on eye exams and glasses.

On YouTube Tony Sizemore of Headbytes has some videos of doing the ports on ProComp 190's in a series titled the Denmark Duo. A troubled series from some outside issues and unpleasant customers, don't let that interfere with the technology data dump. Tony's an old fashion head porter that takes some getting used to but he pumps out a lot of interesting info between episodes of audio blank out caused by his air grinder.

Bogie
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Old 11-17-2018, 12:06 PM
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I believe Headbytes also has a video of the new ProMaxx SBC heads cut through the ports and water jacket on a bandsaw, showing the wall thicknesses everywhere. seems like he also welded a few TIG beads on one, just to demonstrate how good the material is.

I've seen where the earlier edition ProComps don't weld good at all, but don't know what current versions are ,since there are better import SBC castings out there to use now that I work with(ProHeader).


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Old 11-17-2018, 03:03 PM
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I did find Headbyte's videos in my search and have been working my way through them. Yes, he sure seems to know his stuff. His video on the cut up Promaxx head is one reason I'm leaning towards them. I was skeptical at first because he was so positive in his review of those heads it seemed like an advertisement. But, the more videos I watched I could tell that's the way this guy is - if he likes it, he's going to tell you. And, if he doesn't, he's going to tell you that too.
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Old 12-07-2018, 05:15 PM
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Ok, you guys have given me enough knowledge to be dangerous and Iíve been searching and reading like a madman and Iíve got a question about putting together combinations of parts. Given the variations in deck heights, compression heights, piston configurations, head volumes, valve diameters, cam lifts, etc. how can you determine if everything is going to work properly together Ė specifically, if there will be any valve to piston interference? I realize you can use clay to measure this but by that time you own the heads, cam, pistons, etc. and your block has been machined. Not an ideal time to discover a problem. You can machine more clearance into the pistons at this point (which has itsí limits) but other than that, what recourse do you have? And, more importantly, how do you avoid this mess up front?
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Old 12-07-2018, 08:20 PM
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Avoiding problems is the rub, right?!!

It pretty much comes down to familiarity with the engine family in question, and some of the basics surrounding mechanical parts.

For example, in your 351 case....deck height on the block differences really don't impact valve to piston contact problems that much, as the difference is only .023" between the two different block decks....aftermarket pistons generally have a bigger valve notch than a stone stock or basic stock replacement pistons....aftermarket or stock heads still have the valves in the same place relative to left, right , up, down, and height above the piston in the chamber, you have to get into pretty exotic stuff as far as heads go for these things to start moving around and in that case you expect to have to alter parts before it finally gets assembled.

In the case of your 351W, about .540" lift and 245į @.050 duration you then start to get into a territory where you could have a valve clearance issue, but it depends on the pistons and the lobe centerlines and lobe separation. duration has a bigger impact on valve to piston clearance than total lift does, as the piston and valve are closest to each other as the piston is just coming to TDC exhaust push out, preparing to head back down drawing intake in and the intake valve is starting to open just before the piston does reach TDC exhaust, that overlap period when they are using exhaust exiting velocity draw to start the intake flow into the chamber.
Intake valve is only off the seat .050-.300" or so at this point.

I wish I could give you an easy button answer, but that's not the way it works out.
I've put 258į dur @.050", .582" lift with D.S.S. forged flat tops in a 9.480" block, stock '69 4V Windsor heads fitted with 2.00" intake valves and still had over .150 piston to valve clearance on the intake, and over .200" on the 1.54" exhaust valves. 102į intake centerline and 106į lobe separation. Pretty rowdy solid flat tappet.
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  #29 (permalink)  
Old 12-07-2018, 09:35 PM
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Quote:
Originally Posted by Molon Labe View Post
Specifically, if there will be any valve to piston interference? I realize you can use clay to measure this but by that time you own the heads, cam, pistons, etc. and your block has been machined. Not an ideal time to discover a problem. You can machine more clearance into the pistons at this point (which has its’ limits) but other than that, what recourse do you have? And, more importantly, how do you avoid this mess up front?
You probably have seen the generally-accepted minimums for clearance, 0.080" for the intake and 0.100" for the exhaust.

Ericnova72 published a post the other day that said the minimum clearance on the intake valve could be less because the intake valve is opening as the piston is going down the bore on its intake stroke, so the intake valve is actually chasing the piston down the bore. While that is true in most cases, with wilder grind cams, the intake valve is beginning to open waaay before the piston gets to TDC, so a tag could take place if the grind was right.

One thing you fellows want to be careful about when using the clay method of checking clearance.......USE ONLY GRAY, OIL-BASED MODELING CLAY. Other materials such as Play-Doh will not retain their shape between the time you make the impression and the time you measure the thickness of the material.

It has been my experience that if a fellow stays with a modest cam, like no more than 240-250 intake degrees duration and uses the rocker ratio that was used by the factory, he will be unlikely to encounter any interference. I did encounter some measurements that were closer than I wanted to run on a 5-liter build several years ago, using a solid lifter, flat tappet cam and decided to mke my own cutter from an old valve. I uses a 1/4" square cutting bit from a machine shop supply house, sharpened it on my grinding wheel and sweated it onto the old valve. I decided how deep I wanted the new cut to be and made a collar with a set screw to make a stop on the old valve stem. Using the bare heads that I was going to use on the build, I plugged the cutter into the #1 exhaust hole, set my depth collar and laid the head down onto the block without a gasket. I chucked the valve stem up in my hand drill motor and began it spinning, moving slowly down toward the piston crown. It didn't take long at all, because I only had to take a small cut on each piston. Today, I just happened across this tutorial which explains the procedure, but without my collar that I used as a stop or hard cutting bit sweated onto the valve. Oh and by the way, good engineering technology dictates that the crown thickness of a piston will be about 7% of the diameter of the piston. So, 4 inches x 0.07 = 0.280". Almost forgot, Isky used to rent cutters, don't know if they still do.
https://www.bing.com/videos/search?q...il&FORM=VIREHT

I did not see Eric's post #28 before I posted this.

.

Last edited by techinspector1; 12-07-2018 at 09:52 PM.
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Old 12-08-2018, 03:28 AM
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My comment on valve off the seat should have been .050-.200", not .300" as posted in post #28....Just wanted to clarify and too late to edit.
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