header fitment issues

[chevelleshack]

Hello , all . I am working on a 69 mustang with a 351w , edelbrock rpm heads & c-6 transmission . My problem is i have tried two different long tube headers , hooker competition & patriot , & both hit the floor on both driver & passenger sides & there is no way the collectors can bolt up without major cutting & reshaping of the collector or floor . Have also raised & lowered engine to see if different motor mounts would help but it did not . Anyone else have this kind of problem ? Thanks for the help !
Phil

[1985olds]

shot in the dark, but i remeber reading a similar problem with trans crossmembers and it ended up being that the floor was sagging, i dont know if it applies to this, but like i said it was a shot in the dark

[chevelleshack]

Thanks for the reply , hope it is not the floor sagging ! Car is pretty much rust free , floor doesn't look to be damaged & spot welds don't look stressed . Was hoping some ford guys were on here that may have had the same problem . As i figured i got the oddball !!
Phil

[1985olds]

who are you calling oddball, jk. hope it works out for you

[chevelleshack]

......meaning the car not the person posting LOL !! Btw , i happen to like Olds , had a 71 SX & now have a 87 442 wanting an ls transplant .
Phil

[johngross]

351 exhaust ports are higher than a 302 due to the block. Are you certain the headers are actually 351 designed headers versus 302 headers that "should" fit?

[chevelleshack]

That is a good question , the hookers are part # 6901 . They state 302 , 351w but that would make perfect sense as to why they would hit the floor . When i talked to hooker that was never brought up . Even tried another bare 351 block & heads & does the same thing . Possibly would the hooker super competition fit correct ? I,m sure this isn't a rare setup so thats why im confused as to whats wrong . Thanks for the info , will do some more digging !
Phil

[1985olds]

http://www.summitracing.com/search/Part-Type/Headers/Make/FORD/Header-Style/Full-length/Model/MUSTANG/Engine-Swap/Yes/Year/1969/Engine-Size/5-8L-351/?Ns=Rank%7cAsc
maybe give these a try, these are specifically for a 69 mustang with a 351 swapped in.

[chevelleshack]

Not sure why i didn't see those before , will see if summit will take the hookers back & exchange for these . Thanks for the help 85 olds !
Phil

[1985olds]

when i searched headers under the vehicle description bar on the left i put yes to engine sway for the 351, that may be why you didnt see them. summit is normally pretty good with returns, hope everything works out.

[Derek@ModernSpeed]

For a 69 Mustang with a 351W, stock heads, stock mounts and stands, the 6901HKR would be the correct part number. That header was designed to fit multiple platforms (ie falcon and fairlane with 289/302 engines), but is specifically built for a Mustang with 351W not a 302. Which Edelbrock heads do you have? Also, typically when the collectors hit the floor pan, that is a result from the chassis sagging. I'm in no way saying that this is the case, but two sets of headers from two different manufacturer's having the same issue is not likely a "header" problem.

[chevelleshack]

It has the performer rpm heads , not victor jr so exhaust port should be stock . Please no more talk of this chassis sagging thing !!!!! How could i check for this if this is the case ? Car has not been in a wreck ( all original sheetmetal ) & the only rust it has is on the corners of the doors & all the gaps looked good but that still does not mean it hasn't been rode hard . It has had repairs done to the shock towers where they usually break out though . I agree on two sets of headers not working idea ( although the patriot & hooker look almost identical side by side ) so i would rather find out now if i have a chassis problem before i go & get another set of headers . Unfortunately the car is at the blasters & won't be able to check for a few weeks .
Phil

[paul67]

Some engines are tilted down about 4 deg's due to the after market alloy intake manifolds ,if the engine is sitting flat this will kick the hedders up towards the floor,as i found out when i fitted an 95 lt1 which sits flat.What i did was after bolting them up i slowly bent them down you a large dia pipe shoved up the collector.

[1985olds]

hey chevelle, did you ever get this sorted out, curious as to what the issue was

[chevelleshack]

Well , i hope so ...... Got the Hooker super comp headers & they fit ALOT better . Drivers side is still close to the floor but i am changing the 3 bolt flange to a ball & socket anyway so that helps , the passenger side fits perfect . Also looks like there are different transmission crossmembers so i have ordered one for a c-6 ( car was original fmx ) to see if it lowers the transmission any . Hope i am not ignoring a body sagging issue but i don't think that is the case & not sure what or where to start measuring if it was ?? Thanks for the intrest .
Phil

[DynoDon]

the reason ours (Patriot) didn't fit is they were designed for 302, NOT the taller deck height 351.