Major 302 power issues

[TheHenryLegacy]

I have. '91 foxbody with a built 302. I've put so much time and effort into this car, and with the factory AOD auto trans, it won't even burn rubber when floored. It seems sluggish and runs a painfully slow 15 second quarter. What am I missing???

The motor has GT40p heads, Cobra intake, B Cam, open shorty headers (with full exhaust I still had the same problem) stock gears, MSD distributor and wires and some other small mods. The timing also seems a bit off

 

[ashleyroachclip]

what is the gear ratio?
Stock gears for most factory equipped automatics I have seen , were 3:08 or 3:27.
Since you have made those changes to the intake , have you made sure to get the TV cable set properly ?
I would get a gear like 3:73 or lower , as that will wake it up , also consider a different converter .

 

[TheHenryLegacy]

what is the gear ratio?
Stock gears for most factory equipped automatics I have seen , were 3:08 or 3:27.
Since you have made those changes to the intake , have you made sure to get the TV cable set properly ?
I would get a gear like 3:73 or lower , as that will wake it up , also consider a different converter .

Thanks for your input!
I have been told about the gears, I have 4:10 ready to go in, but I didn't think about the convertor. The TV cable?

 

[ashleyroachclip]

The TV cable ,tells the transmission when to shift in relation to throttle input .
If it's not right , you will be buying a new transmission in short order .

 

[TheHenryLegacy]

Aw man. Okay thank you very much for your help, I'll look into it asap

 

[Stopsign32v]

You haven't really done much, and you've chosen parts that were "the ticket" in about 1995. Heads are crap, intake is crap, cam is crap, headers are crap...

Btw I built that same exact combo in about 2003 not knowing any better, except I had aluminum GT40 heads. Was a massive waste of time, effort, and money.

Get you some AFR 185 or 205 heads, RPMII or TFS R intake, and a cam to match them.

 

[TheHenryLegacy]

You haven't really done much, and you've chosen parts that were "the ticket" in about 1995. Heads are crap, intake is crap, cam is crap, headers are crap...

Btw I built that same exact combo in about 2003 not knowing any better, except I had aluminum GT40 heads. Was a massive waste of time, effort, and money.

Get you some AFR 185 or 205 heads, RPMII or TFS R intake, and a cam to match them.

Thanks for your advice

 

[StrayBullitt]

"crap" or not those parts should still be good for mid 200's horse power and 13's. Your heads cam and intake obviously are not the full issue, but rather that there is something else keeping your engine down.

Two things that jump out at me. With the P heads I believe you need to upgrade the valve springs if you didn't do so or you may be floating valves, I've heard even the stock HO cam can float the valves on P heads, but that may not be true.

2nd if you are suspecting there is a timing issue you've got to look into that further, if you're not getting correct advance or if your distributor is 180 off or if base timing is way off, something strange like that, that will kill power.

Might not hurt to do a compression check too just to make sure all your cylinders are healthy.

 

[TheHenryLegacy]

"crap" or not those parts should still be good for mid 200's horse power and 13's. Your heads cam and intake obviously are not the full issue, but rather that there is something else keeping your engine down.

Two things that jump out at me. With the P heads I believe you need to upgrade the valve springs if you didn't do so or you may be floating valves, I've heard even the stock HO cam can float the valves on P heads, but that may not be true.

2nd if you are suspecting there is a timing issue you've got to look into that further, if you're not getting correct advance or if your distributor is 180 off or if base timing is way off, something strange like that, that will kill power.

Might not hurt to do a compression check too just to make sure all your cylinders are healthy.

Thank you very much. It's much appreciated

 

[87hatchy]

I would:

-ensure there are NO vacuum leaks anywhere
-check/set fuel pressure
- get a timing light and check/set the timing.
- replace fuel filter
- put your full exhaust back on. car will be stuck in open loop mode with no 02 sensors to read from. if you have cats, ditch them.
-check/set spark plug gap (id probably actually get all new plugs and wires if yours are very old)
- ditch AC and smog pump if you havent already
- get 4.10s
- realize that the AOD sucks big time and there's a lot of power loss through it. consider a c4 or t-5 swap if you want to go manual
- ensure you have the correct length pushrods and your rocker arms are installed properly (zero lash)


I had the same H/C/I combo as you not too long ago. Yes its not the best you can get, but it should still run pretty strong

 

[TheHenryLegacy]

I would:

-ensure there are NO vacuum leaks anywhere
-check/set fuel pressure
- get a timing light and check/set the timing.
- replace fuel filter
- put your full exhaust back on. car will be stuck in open loop mode with no 02 sensors to read from. if you have cats, ditch them.
-check/set spark plug gap (id probably actually get all new plugs and wires if yours are very old)
- ditch AC and smog pump if you havent already
- get 4.10s
- realize that the AOD sucks big time and there's a lot of power loss through it. consider a c4 or t-5 swap if you want to go manual
- ensure you have the correct length pushrods and your rocker arms are installed properly (zero lash)


I had the same H/C/I combo as you not too long ago. Yes its not the best you can get, but it should still run pretty strong

Thanks much, I really appreciate the check list