Getting car checked, what to look for?

[KickerStang]

Hey guys,

I bought my 5.0 a few months ago and I knew something was wrong with it ever since I dynoed it the first day I owned it. The dyno was really low with 248RWHP/287RWTQ. This is on a 5.0 with TFS h/c/ GT 40 intake. It had other bolt ons. It was missing headers though, so I bought some 1 3/4" shorties, a new o/r x pipe, and catback. It just does not feel that much stronger. 1 reason why I might have had bad dyno numbers is because my distributer bolt that holds the timing in place was loose and it was rotating freely and when I took the timing for the first time, it was only at 5*. So anyways, I also know that I am leaking oil. I replaced the rear main seal and it is still leaking, and looks like it is coming from the valve covers. There seems to have some lifter noise too. So, I know I should have had a mechanic look at it before I bought the car, but it is too late for that now. Now I am having a mechanic look at it to tell me what is wrong with it now. Is there anything I should request, or have him look for? Thanks.

 

[stephen4785]

he should do all of the basic checks for you but make sure he does a compression check,cylinder leak down test,coolant system pressure check,make sure your alternator and battery is good,no excessive slack in the rear end, see if he is able to check your fuel/air ratio, and check the fuel pressure.this should give you a good idea about how your car is running.Hope this helps.

 

[stangbear427]

Not saying this is your problem, but one thing jumped out at me- IMO, 1&3/4" primaries are too big for your engine. It's killing your low end, maybe the whole powerband. Put some 1&5/8 headers on if you can, and see how it feels.

 

[KickerStang]

I already had in mind the compression test, leakdown test, and coolant pressure test. When I had my a/f checked on the dyno from the tailpipes it was so lean it was off the charts during the low to mid range RPMs then came down and fattened up a bit, but was still at 13- 13.5 at peak HP. My fuel pressure at idle according to my fp guage is at 40-42 psi.

As far as the 1 3/4 headers are concerned, they may be too big, but when are they ok? If I get a stroker would that be ok? I am very upset about my low end tq because I also have the TFS #2 cam and that has NO low end TQ. When I looked at the dyno sheet the TQ was low and really flat, then at 2700 RPMs it started to go up from there. I would like alot of low end tq, so once things get fixed with my car as far as mechanical problems, then I will focus on performance parts. I have to say those headers were a pain to install because of the width of the headers. I think if they were 1 5/8's the would have been easier.

 

[stangbear427]

As far as the 1 3/4 headers are concerned, they may be too big, but when are they ok? If I get a stroker would that be ok? I am very upset about my low end tq because I also have the TFS #2 cam and that has NO low end TQ. When I looked at the dyno sheet the TQ was low and really flat, then at 2700 RPMs it started to go up from there. I would like alot of low end tq, so once things get fixed with my car as far as mechanical problems, then I will focus on performance parts. I have to say those headers were a pain to install because of the width of the headers. I think if they were 1 5/8's the would have been easier.

Usually when you look at part numbers, they are for the 351's and the 1&1/2-5/8 are for the 302's. You wouldn't think an eigth of an inch would make that much difference, but when you add it all up it's a full inch more exhaust rushing out. You have to have enough air coming in to justify it, and with under 300HP, you just don't. Now, throw some un-natural aspiration on there, and that may be another story- but rule of thumb, they want a lot more displacement to be of any use. It's like running a full 3" exhaust on a stock Honda Civic. That's where a stroker may come in, jump up too a heavy breathing 347 with a nice longer stroke and you may have some exceptional top end power from them, but you still won't have great low end torque on a naturally aspirated smallblock unless you step those headers down a size. I don't see spending a couple thousand dollars on a stroker so you don't lose a couple hundred on headers, but whatever turns you on

edit: oh, I think you need more timing too. 5* isn't enough. Try 10-14. How do your plugs look? What size injectors do you have? Is your Pro-M callibrated for them? You seem to have a bit of a fuel issue going on. Make sure your MAF is clean, filter is good, injectors are clean, are you running high test? You may just need a good tune up.

 

[stangbear427]

oh, I think you need more timing too. 5* isn't enough. Try 10-14.

Crap! I was all logged off and heading for bed when I thought of something. You bought the car with all those parts installed, except the headers? So you don't know how the cam was degreed, it could be advanced or retarded, or if you have multiple keyways on your timing chain sprocket, which could also be advanced or retarded. I still think you should try bumping the timing a little more, but be carefull- not knowing this stuff can really change the outcome! Check your plugs and your A/F ratio a lot while experimenting to be safe.