I'm looking for more power for my 73 302. I think stock the engine has about 140hp. Does any one have any experience swapping in a Edelbrock Performer RPM intake and late model 5.0 Explorer heads (GT40P). I want to do this and also add a Holly Truck Avenger carb and a set of headers? I read an article about this swap on a 351W in Car Craft (Jan 80). The Article was called Junkyard Jewels. I want an engine for torque not top end HP. I don’t want to go the fuel injected route. I want trail fixability.

 

that combo works good (gt-40 heads and performer). if you buy a 351w lightning motor it will fit your bill perfect. already has the gt-40 heads, slight cam, little more compression and oh yea twice the power.

 

Spart, I installed a set of the Ford Racing aluminum roller rockers, 1.6 ratio for pedistal mount 77 and newer. I had to rejet the carb and I can really tell a difference in the way it revs and pulls.
74Explorer,I would recomend this upgrade as a performance mod worth the money.
Some headers won't work on the P heads, so make sure they specifiy.
Don't spend ALL of your money on the motor,you are going to break some parts!!!

 

what jet are you running in yours now? now it is starting to warm up it is time to get the jet right on the money now. and did you put a bigger center squirter in yours if so how big did you go? mine has a very slight stumble at first tromp.

 

I was worried that the Performer RPM would be too much for top end. Is there a big difference between the Performer and the "RPM". I was thinking about swapping in an a square bore 69 Ford intake for low end torque. Will I need to swap cams? And does anyone know what good cam specs look like for a 4000lb truck, 3.50 gears, and a 302? I have had bad experiences with bigger cams loosing all low end. Hot Rod said none of the factory intakes were very good but I don’t know if I trust them because they might just say that to help Holly and Edelbrock sell more parts and get more advertising dollars. The GT40p heads are suppose to be better than 69 and 70 351 heads. Any input is appreciated.

 

i would run a performer and a towing type of cam. you want off idel to mid range power not one that starts making power at 2500rpm-6000rpm. they sound cool but not to pratical for what you are trying to do.

 

Car Craft magazine did a dyno comparison on a small block chev with all three intakes, Performer, RPM, and Torqer. They showed that there was almost no loss of torque at 1000 rpm but a good gain starting somewhere around 4000 with the RPM vs Performer.
As for Jetting the Holley I am back to 66 primaries but still running the 4.5 power valve. Try tightning the spring on the accerator pump arm. This may get rid of your flat spot off idol.
I would take a look at the performance line of cams that Ford offers. A mild roller cam will make the most off idol torque and rev too. As for the GT40 heads vs 69W heads, the GTs have smaller valves wich should help low end torque, and hardened valve seats. The price of brand new heads from Ford is very reasonable. Somewhere around $550 a set.
Spart, I can run richer jeting empty but not while towing. If you don't tow than you may not have any problems. They claim 10-15 hp with the roller rockers and I believe it. I have a full mechanical advance distributor and I am starting to think that has somthing to do with my low end rich condition. I am going to do some testing with timing to try to get rid of the rich condition. With my setup the Holley should have been preaty close out of the box.

 

why do you think the dist would cause a low end rich condition? where is your base timing and the timing at full advance? i converted mind to the duraspark. it works very well and if something did happen to break down i would be able to go to any parts store to get parts to fix it and me back home.

 

I think the Holley was jetted for vacume advance. During cruise mode, light throttle, timing is advanced to full advance wich requires richer condition to prevent detonation. At least that is the way I understand it. I know that a lean condition can cause detonation in a higher compresion engine without severe advance.
I have a buddy that has one of the Snap-on timing lights that has a meter that shows advance. I am at about 12 at an Idel and a total of around 32. I don't think the advance is coming in soon enough.
My distributor is a Davis Unified ignition unit OR gm hei for short. I know, but at least it's not a steel body 32 ford with a 350/turbo350 combo.

 

I made the conversion to a summit HEI in my 71 Chevy shortbed. It's a 2wd. An HEI makes a big difference so I was wanting to go the DUI route with my EB.

68-351, Was that an easy swap... one wire hookup? The other issue is, did you swap in a new cam when you changed distributors? I was wondering if the wear on the cam to distributor gear would be a problem? I really dont want to tear into the bottom end of the engine if I dont have to. I figure with just 57K good oil should keep her going another 50k or so.

 

i know that hei is a easy swap, but i would have had a hard time sleeping at night with it. the durapsark ford ignition is a pretty dependable and not so expensive conversion. came stock on the 76-up broncos. i sleep better with it and it works gread. 8 degrees at idel and 35 total advance.

 

What? You don't like the HEI because it it's a GM peice?

 

Yes this is a Ford sight and most on here would not be proud of my actions.
So I would like to take this time to make my appology.
It was very easy and when you order the dis. you pick wich gear steel or bronze.

Spart. Who would have thought that a set of good rocker arms would lean out my jetting?
I am going to try going back to the stock settings on the 670.

 

if the ratio stayed the same then i doubt that you changed anything. if the ratio on the rocker was biger then you added more lift to the cam and made it worse. i used to drag race and if all you did was change to roller rockers on a mild motor then your e/t would not really change unless you went to a rocker with a bigger ratio thus giving the cam more lift. so in a bronco that you are going for low end to mid range power ??? i hate to say i would not have bought them unless my stock ones were wore out (sorry). the roller rockers are deffinetly better than the stock ones and have less friction, whether it is enough to notice ??? when i was running built motors on the street and they were loading up at idle the first thing i would do was go to a 25 power valve. with a bigger cam you have less vacume at idel causing the valve to open at idel or real low rpm. also it does not take too much to blow a holley power valve. hwo big of a cam do you have in it?

 

The ratio didn't change. stock stamped rockers are 1.6 on a Windsor and the rollers are 1.6. I wouldn't believe it ether but It is definatly wanting more fuel off the bottom.
It use to sign off at 5500 and now it keeps pulling.
It may just need the bigger pump squirter to get rid of the flat spot.