Thumper heads

19s will work with thumpers and bolt ons like you want. Upgrade the pump and stick with an AFPR and your good to go!

FOOT2DFLOOR said:

I dont have anything against the reliablity of thumper heads but i put them on my car and only gained 2 tenths in 8th of a mile. needless to say i was pretty dissapointed. So now im saving up for some AFR 185's.

1991 LX coupe 5.0
Edelbrock Performer intake, E303 cam, Thumper Performance ported heads, BBK pulleys, BBK cold air, smog pump delete, and a 3" exhaust with a custom H pipe and 2 chamber flowmaster mufflers.

Click to expand...

Not trying to arue with you here, but I think there is another reason for that. What exactly did you run in the 1/8th before and after? Is that it? Any suspension, tires, gear???I didn't see much of a gain either with a lot more than just doing Thumpers, but I just seemed to get more and more of a traction problem. My old combo:

CAI, 76mm MAF, 70mm TB+EGR, Edelbrock Performer 5.0 Intake, Thumper Heads w/ spring upgrade, B303 cam on 1.7RR's, BBK 1 - 5/8ths LT's, 2.5 o/r H - pipe, 2.5" Flows dumped, 3.73 Gear, front swaybar deleted. Some other misc stuff.... like pullies and some deletes....

I ran 8.4 at 82mph at an old track that everyone ran .2 faster at other tracks. It seemed the more parts I put on it, the more I had to baby it. I ran a 8.89 at 79mph with only the MAF, gear, CIA, pullies, a few deletes, and flows. Did full suspension, somehow the ET stayed the same but the MPH jumped to 85mph. I was running 275/40R17 Nitto's on Cobra R's, I couldn't launch over 1800rpm, so never got to use the suspension. Yes the car was only quicker by .4 after all that, but in a roll race, or especailly any street race, there was a HUGE difference.

A lot has changed on my combo since then, including the thumper heads but what I am saying is that I think they have more potential.

Yeah you'll need an adjustible FPR if you keep the stock injectors. I run mine at 41psi and the timing at 15 degrees advance and it performs realy well. Its actually stoich on the passenger side and lean on the driver side at 40 psi, so I've got to figure out whats going on there, now at 41psi its slightly lean on the driver side and rich on the passenger side.

Naples Fl....?? Swamp??? LOL! If the cooling system is good you will have no proplems with overheating... any heads!! cool?? There are 5.0s in the 12s with 19 lb injectors and an adjustable regulator, and 65 T/B and a small cam.. the upgrade to 24's might be needed in the future if you keep building the engine with different cam/gears/higher rpm ect... but you should be fine!! remember, from what I saw on TV you cant go fast on those highways anyway.. OH.. wait... that was because of Weather!! ( Ok bad joke!! my bad!!) All that mess keeps missing Jacksonville!! ( knock wood!!)

I feel the iron heads will do fine!!
Have fun..
Just me.................................

Thumper

I assume you have enough money or could save the money for aluminum heads. You gave a good reason on why you were skeptical about them so what I would do if I was in your position is get a set of GT40P heads then have them ported with a 3 or 5 angle valve job.