PontiacBonnevilleClub.com

Im begining to think of mods to do to this car, I already have the 180* thermostat, needs to be drilled- but only when i get a replacement bleeder valve. I will be buying the FWI soon. After that is where Im lost. I was thinking about upgrading the exhaust as far as buying the Intense headers and then buying the hi-flow cat they sell. It may be some time before I do this as Im back in school (lack of money for projects), but it will be done. But any input on the situation would be greatly appreciated.

Intense doesn't make headers, they sell SLP's headers. For the price, you're far better off getting the cheap eBay headers and making them fit...

Don't get the cheapest ebay headers and make sure to read the full description.
There are a couple sellers trying to pawn off their scrap metal as "needing some modifications" to fit -the work required to make them fit will be well more than the $40 difference between their junk and the $200 Speed Daddy's which fit well. As with all the cheap header kits though, don't waste your time using the supplied gaskets or clamps -get the real clamps and metal gaskets or you will have a lot of fun with exhaust leaks and blown out paper gaskets.

I'd recommend some more mods with or before headers. Otherwise you've wasted your money and won't get the full potential out of them if you don't go further than an FWI. Smaller pulley and rockers or a cam will open it up and a tune. If you don't plan on going with rockers or a cam then I'd suggest to go for a ZZP PLog and 3" Downpipe rather than headers.

I'm running SSAC Headers, which are pretty much the same thing as the speed daddy's. I'd definitely recommend getting some wide band clamps from Napa, another flex joint and getting anything welded in that you can. I left the flex joint that came on them and it's leaking pretty bad now, it's only been 3 or 4 months. And I'm also fighting an exhaust leak from the front header to crossover connection, I'll probably have that connection welded shut when I get the flex joint replaced.

If you plan on installing them yourself you're in for a treat. You will likley have to modify them in some way. The biggest issue I had was I had to cut about 1-1/2" off each end of the crossover pipe to get them to fit properly.

I agree, headers are way too early on this menu.

You need some appetizers first. Headers are dessert.

One reason to go with headers this early is if you *ABSOLUTELY WITHOUT A DOUBT* will be modding to a level where headers will be beneficial in the near future.
Even so, on a stock supercharged 3800 (Series II) headers might take away slightly from the low end, but will liven it up in the mid-high rpms, as well as significantly lower the likelyhood of KR on even a stock pulley (yes, it happens more often than most people realize, although the quality of the fuel you use can effect KR immensily).

I was planning on installing the rockers eventually and the smaller pulley, though i dont know if i want to mess with the cam. But any of those mods probably wouldnt be for a year or more, especially the rockers cause all the work i just did to the engine. Though i just did my LIM gasket, i wanna get the manifold ported in time, how long should i wait to undo all that? Or is that a matter of how often the car is driven?

olblueeyesbonne wrote:One reason to go with headers this early is if you *ABSOLUTELY WITHOUT A DOUBT* will be modding to a level where headers will be beneficial in the near future.
Even so, on a stock supercharged 3800 (Series II) headers might take away slightly from the low end, but will liven it up in the mid-high rpms, as well as significantly lower the likelyhood of KR on even a stock pulley (yes, it happens more often than most people realize, although the quality of the fuel you use can effect KR immensily).

This. I plan on cam-ing mine, that is certain (at least at the moment). But I had a PLog and 3" DP and intended to stick with that setup for a while, however an odd accident busted my rear manifold, flex joint among other things and I found that for less than $50 more I could get headers vs. replacing and repairing the exhaust, so I went with it.


Usually with these motors people either go rockers or cam, not both unless you get the stock ratio rocker. Rockers would only involve pulling the valve covers and any accessories that are in the way (i.e. alternator etc.). A cam would be more involved, but in any case you shouldn't have to pull the LIM back up if you're worried about that.

If you cam you have to remove the LIM to get at the lifters.

Oops, I wasn't thinking about that.

Unless you roll the car over on it's roof and the retainers will hold them in.

I did this on the last engine................but it was on an engine stand instead of in the car.

Headers open up the top end, which is where the 3800 falls on it's face. I'm not a fan of the Plog, anything that unbalanced the engine like that is bad IMO.

The idea of the Plog was to better "balance" the engine, as the front manifold is far more restrictive than the rear.

It wasn't the lazy man's way of creating power by replacing the one easiest to get to, there was a reason for it.

Well i know that ill do the rockers for my car eventually, how are the ones from intense-racing? I was also looking at the medium load valve springs too, they seem like they would do the job when i get my rockers.

Also, whats a shift kit? And how hard should it be to install one?

jedwards83 wrote:The idea of the Plog was to better "balance" the engine, as the front manifold is far more restrictive than the rear.

It wasn't the lazy man's way of creating power by replacing the one easiest to get to, there was a reason for it.

So why do they suggest skewing the front injectors up about 3%?

BonneMe wrote:

jedwards83 wrote:So why do they suggest skewing the front injectors up about 3%?

That's interesting, I have no idea TBH. I wonder if GM accounts for this in the ECU software; the front manifolds are a bad design and poorly cast.

The best option is to SMAW the 'neck' of the front runners with nickel rod, then port them to match the rear. That's better matched flow front to rear.

FYI, you don't have to skew the injectors in the PCM. You can buy a set of skewed INJECTORS. But I agree, it's just dumb. It should match.

00Beast wrote:Intense doesn't make headers, they sell SLP's headers. For the price, you're far better off getting the cheap eBay headers and making them fit...

I disagree VEHEMENTLY with this... I've seen cheap headers rust through, break welds, blow gaskets, or just completely not fit. SLPs are the best-fitting headers on the market for the 3800, have the best coatings, the best welds, and are absolutely guaranteed to fit. The only modification needed is to swap the dipstick-tube for one from a W-body. Add on a 3" SLP high-flow, and you have the best equipment available.

The only drawback to SLP are the price, and a tick from the DP flex-joint that can be fixed easily if you want.

Arent the Speed Daddy headers SLP knock offs ? I would think they would bolt right up too then? I did email SD and they responded saying.... Thanks for contacting us. Sorry, unfortunately these will not be compatible with a Bonneville model. We don't advise modifying this into your car.


Any thoughts?

speed daddys will work,