[DeTomaso] Questions on 4v heads

[Asa Jay Laughton]

I've been running MPG port plates (both intake and exhaust) on my Mach  
I since 2001.  I was mostly concerned about low speed driveability  
with the rumpy cam and 4V quench heads.  I have -not- been  
disappointed.  I have no dyno sheets to prove anything, but I -do-  
think they have improved my low end.  I'm also running a stock 4V cast  
iron intake, so I have a pretty big step there at the port plate as  
the air comes into the head.

Strictly seat of the pants feel.
Asa Jay

Quoting cengles at cox.net:

>
> Dear Jack,
>
> About twenty years ago I used MPG intake and exhaust port plates.   
> While I thought that they made more power, that was mostly a hope   
> and a guess and it was never measured. In my review of exhaust port   
> plates, they are usually described as improving exhaust flow and   
> they usually *imply* improved power, but I could never find any dyno  
>  evidence of actual benefit.
>
> Recently Dan Jones' Great 351C Dyno project actually tested the MPG   
> Stinger Port "plates". They are bronze and have a solid tongue or   
> stinger of brass that sits low on the floor of the exhaust port.   
> Dan's dyno testing showed (I am going on memory here and I have   
> slept since he posted it) only about 5 horsepower improvement. It   
> was way less than 20 hp.
>
> I think that properly used with a complimentary intake manifold and   
> cam, intake port stuffers can give an honest 20-30 hp. I think that   
> the HP benefits with the exhaust port stuffers is much more modest.   
> [....but five hp *is* hp....]. Cost per the MPG website is $90 for a  
>  set of intake&exhaust stainless steel port plates and $175 for a  
> set  of Exhaust Stinger Port Plates. Again, as I glanced at the  
> website  they allege 20 hp and 20 ft-lbs improvement with their  
> steel set,  but not dyno sheets are shown nor provided...........
>
> Warmest regards, Chuck Engles
>
>
> ---- JDeRyke at aol.com wrote:
>> In a message dated 10/25/10 7:19:04 AM, dave at damardirect.com writes:
>>
>> > Hi Jack,
>> > What is your opinion on exhaust port plates? W/o intake port stuffers?
>> >
>> Never actually used either; I got lucky in 1990 and found a lightly used
>> pair of SVO aluminum heads that already had closed chambers, adjustable
>> valvetrain and raised ports. Generalizations are worth what you pay  
>>  for them ($0
>> here), but my understanding on 351-Cs is,
>> 1)- intake port stuffers can make maybe 20-30 bhp extra (~10%) on a real
>> 350+bhp engine, at some rpm levels, depending on the intake & carb they're
>> paired with.
>> 2)- Exhaust plates do less than intakes but can pick up maybe 10-20 more
>> bhp (~3-5%) on a real 350+ horse engine, again over certain rpm levels. Lots
>> of caveats- including starting with closed-chamber iron heads, semi-equal
>> length headers and more open exhausts than stock Ansas. There are 2  
>>  designs I'm
>> aware of: cast-stainless or cast-bronze to take the heat, and are bolt-ons
>> between the heads and header flanges, not welded, pinned or glued.
>> Port plates are Band-Aids for head design problems. Both intake or exhaust
>> plates need replacement or at least tuning of other engine parts for most
>> drivers to even notice them except that they may change the exhaust note. A
>> couple of vendors sell these; I'd call around and ask them what   
>> effect they've
>> seen on something like your engine- and have a parts list handy 'cause they
>> will ask whats in there. FWIW- J DeRyke
>> _______________________________________________
>>
>> Detomaso Forum Managed by POCA
>>
>> Archive Search Engine Now Available at http://www.realbig.com/detomaso/
>>
>> DeTomaso mailing list
>> DeTomaso at list.realbig.com
>> http://list.realbig.com/mailman/listinfo/detomaso
> _______________________________________________
>
> Detomaso Forum Managed by POCA
>
> Archive Search Engine Now Available at http://www.realbig.com/detomaso/
>
> DeTomaso mailing list
> DeTomaso at list.realbig.com
> http://list.realbig.com/mailman/listinfo/detomaso
>



-- 
Asa Jay Laughton - sent from somewhere other than home
******************************************************
http://www.racingagainstautism.com
http://www.teampanteraracing.com