351 roller. Sorry but I need some opinions please.

[Hank_]

I am writing this and not wanting to because it seems like every day there is a new engine build thread. I have spent hours reading posts on heads and cams and I just would like some answers to a few questions.

First my needs: The Bronco will be 95% street driven. Not because I dont love to wheel but because I will drive the bronco every day all year long. When I do off road it will be sand dunes summer, snow in the winter, and some trails in the spring. No real rock crawling unless I were able to do the once in life time trip out west.

The engine is a 351 roller out of a 1995 f250.

The trans is a ZF 5 speed.

The tires are 35" and the axle gearing will be 4:56.

I have to pull the heads and get a valve job. While the engine is apart I figure I could if reasonable do a couple of upgrades if there are any. I am NOT looking for a 400hp engine.

Is there any value in changing heads. I am going to have to have the stock heads redone with new valves due to a burnt valve. I dont want $1000.00 alum heads but to put a set of GT40 iron heads compared to the stock 351 heads.

What about a cam upgrade. Is there a cam that would work with the above heads (or like heads) and give a little more power. I dont want different rockers just an upgrade in camshaft.

Exhaust will be BC broncos headers and 2 into 1 exhaust.

The engine will be fuel injected and have an explorer serp set up.

If I can get some low cost horse power if there is some to be had and this is the time to do it.

Again I am sorry about this as is seems like much has been written but I am having a hard time putting together all the threads to come up with what I am looking to do.

Thanks for the input.

Henry

 

[Nightstick]

It sounds like you've got everything figured out already. Your parts choices are virtually identical to mine with the exception of my decision to go all out on the motor. The GT-40 heads would be a good and cheap upgrade. The factory cam, or new one with similar specs will serve you fine.

 

[Bronchole]

Don't be afraid to consider a custom ground cam. Talk to a cam grinder and see if they can offer you a cam taylored to your needs and cruise RPM. It's not like you need to have an off the shelf replacement available. The cost is very simmilar to stock and aftermarket grinds.

BTW, make sure your headers will work with the heads you are selecting.

Just something to consider.

 

[Broncobowsher]

There is a little to be gained going to some better factory castings. Gen1 lightening are GT40 and bolt right up. The Cobra and '96 Explorer will require drilling the bolt holes out for the larger bolt holes. I would avoid the P-heads simply for the exhaust clearance issue.

Step up to a stock mustang 5.0 cam would be nice. Aftermarket I would look at something like Crane powermax 2020 (if the valves are able to support the .530 valve lift).

 

[COBlu77]

I have essentially the same thing you will have, except with a 4R70W auto tranny. My engine is completely stock, as far as heads, cam and exhaust. It has plenty of power for a short wheel based daily driver. It's equivilant to the torque and power that I have in my 04 F150 with a 5.4. It's a fair amount stronger than my 95 BB with a 5.0. At sea level you should be pretty happy. I do a fair amount of mountain driving with mine at altitudes from 5300 ft to over 10k and I can maintain 55-65 on all the passes easily in 3rd gear.

I've tried a couple cams and have been the happiest with the stock cam. My MAS air Mustang A9P computer has been happier with the stock cam, too. I think you'll be wasting money to just add better heads or a cam. Unless you're ready to pony up for the whole enchilada -heads, cam, exhaust, injectors, MAF, throttle body, and custom dyno tuning, as a complete system, don't waste the money. I initally tried a mild cam and was unhappy with the power band. It raised and narrowed it a bit. It also tended to run lean with the non-stock cam.

 

[broncnaz]

I'd probably leave the factory cam in there as with your gearing combo, tire size and OD tranny you will benefit more from keeping it then swapping to a bigger cam as you may lose some lowend with a bigger cam. GT40 heads would be a good upgrade as they have the larger valves like the early 351W heads had. I would also consider getting the heads milled to boost the comp ratio a little. although not really required.
Although your best low cost HP boost would be from aftermarket heads. There are plenty of cast iron heads out there that are way better than anything out of the factory. World products windsor JR or SR heads would be a good choice and could bump your HP up by about 40-50hp alone.

 

[needabronco]

How many miles are on this mill, and what condition is it in (a burnt valve answers that one...)? I ask because putting fresh heads on a high mile engine can and will cause bottom end issues such as excessive blow by. I've done a few valve jobs on 150K+ engines only to tear them down soon after because the rings are shot...

It could be money well spent to just go ahead and tear it down and inspect what you've got. If your lucky it'll just need a hone job and a set of rings and bearings....

Or just roll the dice:-X

 

[jedblake]

Needsabronco nailed it. All hotrodders and engine builders I know would not take this chance. A fresh top end is not compatible with a worn lower end. Just pull the engine, inspect, mike, and take it from there. Condition of the block and internal components will lead to rebuilding.
Jed

 

[Hank_]

Yes I agree and I will take a look at the bottom end. I am hoping to be able to re-ring the same pistons. I will know more in the next couple days. I am going to run the engine and trans to the car wash and power wash them and then disassemble the engine. Thanks for all the input. I would still like some cam numbers for cams others have used. Where do you buy a new stock h.o. cam?


Henry

 

[broncnaz]

Used roller cams should be fine as there is very little wear involved with roller cams. A roller cam is the only cam I would consider buying used.

 

[Hank_]

Found a 96 explorer engine near me. It has the gt 40 heads, front tensioner set up and the upper intake I can use. I will pick it up this weekend. I will try to have the rest of the engine disassembled by this weekend and get the ball rolling on the rebuild. If my cam is in good shape I will reuse it. I haven't found a good replacement cam and the E303 has mixed reviews. Parts will be ordered next week for the rebuild and I will keep updated on the progress.

Henry