351w rebuild/keep emission legal

I have a 1990 fuel injected bronco, we are goin to do a rebuild 351windsor and i need some pointer on how far i can go and still pass ga. Emissions. I need a good bit of torque being that its lifted and take it boggin. Any ideas of wat to do and get?


Register now (free) or login to remove ads

What gears?

you need to have cat converters on it. They need to appear OEM or equivalent replacement
The gas cap needs to have its seal and appear untampered with.
From what I see they run a dual stage accelerated stimulation mode, meaning they run the sniffer up the tail pipe and accelerate on the dyno .
The 96 and newer cars have it easy, just a gas cap test, an OBDII check and a visual of the cats.No tailpipe sniffer.
With a fresh rebuild and mild performance parts you should be fine, however you may want to keep stock wheels and tires handy for test day, so the engine doenst have to work its heart out pulling the big rubber, burning way more fuel, failing the test due to excess emissions caused by working the engine too hard during the acceleration tests.
If it has an AIR system be sure it works properly.
When the test is done , if you fail you may have the right ( I would hope so) to request the printout of the test to determine it was performed correctly.
with a fresh rebuild, new plugs etc,correct thermostat(warmer engines run more efficient) timing set correctly and corrected for any altitude the vehicle is operated in, you should be good to go.
If it fails and you try to get it to comply,keep your receipts for the work performed. If you spend 736 (I think) dollars to try and rectify the trouble and cant get it fixed, you can use the receipts as proof of trying to repair it and they can grant you a waiver for the year. That is a lot of money. It is only 170 some dollars here in pennsylvania. Maybe someone should protest that.

do u think i can run 10 to 1 compression?

I wouldnt get carried away with compression ratio or big cams and such.
The 351 heads are designed to flow for torque as they are heads for a truck ya know?They are not a high cfm flow head as compared to say a set from a 5.0 HO stang.

RV cam and 9 to 1 compression would be plenty. 9 to 1 with an rv cam and would supply torque for muddin and such. Besides you have the option for low range when muddin , a six cylinder would pull it - truthfully.
Keeping the (static) compression down will help keep the dynamic in check with an rv cam, which in turn can help keep the NOx in check.(oxides of nitrogen) This is important as the tailpipe tester tests for NO and HC and CO. High compression and heat will create lots of NOx and fail the test.
The cat converter keeps the HC and the CO in check by converting them into CO2 and H2O. Having a good converter on the rig and keeping the engine at the proper temp and timed correctly, along with Proper EGR function, will ensure a pass.
New O2 sensors will almost certainly be a must.They are pretty critical when it comes to maintaining a 14.7 to 1 stoich. I know this is a lot to grasp, but if you make a checklist and be sure everything is in line you will do fine.
Also if you fail, a copy of the gas analyzer report can help to narrow down where you may have an issue , so keep track of that piece of paper.

Best thing you should start with is right here http://www.summitracing.com/parts/TFS-51400004/ these are 50 state legal.Anyone that knows their Fords will tell you the stock heads are the SBF's biggest draw back,both Crower and Crane offer compu Cams that can work with emissions equipment give them a call for Tech advice.