This is topic Exhaust question... H pipe or not. in forum Tech Talk at Northern California Ford Owners .
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Posted by Chris_67_SC_408 (Member # 936) on
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This is what I'm doing.I have a 351w bored .030 w/ a 4" stroke making it a 408. The whole bottom end is forged. 8.5:1 compression. Trick flow track heat heads and intake. Holley 75mm tb. a hyd roller .236 int/exh @.050 and .544 lift int/exh. 50 lb injectors. and a novi 2000 w/ 10-12lbs of boost.
Now this is my question. I just bought a set of 1 3/4 long tube headers and i'm planning on having 3 inch exhaust all the way back, should i get an H pipe or just have two straight pipes with mufflers? 
Posted by 88gt (Member # 579) on
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.[ March 25, 2002: Message edited by: 88gt ]
Posted by st5150 (Member # 51) on
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I thought only the TFS "R" intake was avaiable with a 351W lower? Regardless, track heat heads are going to be really dinky for a 408.... let alone a boosted 408. Why are you putting on heads meant for motors with over 100 less cubes on that thing?
As for the straight pipe vs H pipe goes, I've seen dyno test (and proven with my own butt dyno) that the cross over pip (the " - " on an |-| pipe adds power at lower RPM's. If you stick with those dinky TW track heat heads on that boosted 408, power down lower RPM's will be the least of your concerns.
Posted by shade-tree (Member # 298) on
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there's a new trick flow intake for the 351 with a 90mm opening and is called an 'R' intake, it's even bigger than the 302 'R'.
(saw a post on the corral about it)hmmm... junkyard 351w, + AFR 185 + new TFS-R, + BIG cam... hmmm...
(die 302, die!!) ![[worship]](graemlins/worship.gif)
Posted by ScuEleanor (Member # 785) on
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Hey I am building a 408 windsor stroker as well. I heard that straight or crossover pipes don't make much difference. About the heads, I am putting on ported Victor JR. Heads. Either these heads for your application or some ported AFR 185 or AFR 205s would be sweet (need custom headers for 205s). These will make much more horsepower than any street heat. Where did you get your engine and are the pistons, rods, crankshaft forged? just curious, hope this helpsDavid
Posted by Chris_67_SC_408 (Member # 936) on
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Yes the 351 intake has the "R" upper and 351 lower which combined puts the power band between 1,500-6,500 just like the track heat. Which head (that can be used with stock headers) would you suggest? The reason I went with trick flow heads is because the pistons (which i got a good deal on) had reliefs cut for trick flow heads and i couldnt use stock 2.02 valves with them. The pistons got here after the heads and i was pissed because the pistons have two sets of reliefs cut into them. I am not building some 9 second car here, the plan is to build a fun car to drive around on the street. The car has dinky tires and completely stock suspension and the track heats are good budget heads.
ScuEleanor,
Yes the bottom end is all probe industries crap. The crank is a lightend "dominator 4340" with cleveland journal diameters because it's an svo block, the rods are "ultra lite 4340" 6.250" i beam rods, and the pistons are forged alum dish top pistons for 8.75:1 compression.
Posted by st5150 (Member # 51) on
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quote:
Originally posted by Chris_67_SC_408:
Yes the 351 intake has the "R" upper and 351 lower which combined puts the power band between 1,500-6,500 just like the track heat. Which head (that can be used with stock headers) would you suggest? The reason I went with trick flow heads is because the pistons (which i got a good deal on) had reliefs cut for trick flow heads and i couldnt use stock 2.02 valves with them. The pistons got here after the heads and i was pissed because the pistons have two sets of reliefs cut into them. I am not building some 9 second car here, the plan is to build a fun car to drive around on the street. The car has dinky tires and completely stock suspension and the track heats are good budget heads.
I'd talk to shops with experience with your pistons (Anderson, Bennett, ect) and see what heads would work better with it. Some Victor Jr's or AFR 185's will make roughly 40ish more HP with everything else the same.
Posted by Chris_67_SC_408 (Member # 936) on
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Yeah i saw the flow #s on the 185s vs the tfs and they were pretty damn close except the tfs heads flowed better at low lift and the 185s flowed better at high lift. I figured the better flow at low lift would help out at low rpm and the charger would make up for it on top end. But then i saw the head to head comparison in the new 5.0 or mmff or which ever mag it was and the 185 made more power the whole way through.
Posted by PunkINa5.SLOW (Member # 10) on
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If you have TFS pistons then send the heads to TEA or go with some TFS R heads.The h pipe doesnt make sense to me since I think exhaust is like water and takes the path of least resistance.
Meaning that I dont see it taking a 90 degree turn into the H pipe.
I do see and feel the X pipe helping. That is what I have.
Posted by PunkINa5.SLOW (Member # 10) on
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Also can I ask why you like the single pattern camshaft?
Posted by 1sicgt (Member # 714) on
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I agree with the analogy of the X vs. H pipes. I think the x-pipe is a better design becuase it forces the two flow patterns together making the extra back preasure.
Posted by Chris_67_SC_408 (Member # 936) on
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I've actually already planned on having the heads ported after the first blown head gasket.
I've also heard from a few people who run superchargers that X pipes will actually restrict flow on a supercharged motor.
And as far as the cam goes, I called like 5 or 6 cam companies and told them exactly what i had and ask what the recommended and after getting 6 COMPLETELY different answers the grind Schnieder recommended made the most sense (some were in the .250 @ .050 range and some where around .210 @.050 range). When i asked if 5-10 degrees and .1 or .2 more inches of lift on the exhaust would be better they said no that the heads I'm using will run better with a single pattern grind which didn't make much sense to me since the TFS cams which are designed for those heads use a bigger exhaust lobe. But I figured I was just a dumb kid and that I should just listen to what the professional says, so I did.And here is a new question.
Will 3" exhaust with 2 chamber flowmasters be okay as far as noise or will it be annoyingly loud and should i go with 3? Too loud means you get a head ache while cruising on the freeway.