Engine 302 Roller Build

08GT500 said:

Hi,
Most importantly, the two most crucial questions...What’s your budget & What are your HP/TQ goals? How strict Are the emission laws where you live? This is a bone stock car; all emissions equipment in place, motor, suspension, brakes, gears, stock? Is it a 5 speed? Shop assembling the shortblock & longblock assembly?
For now, I’m a nutshell....
The stock heads are quite restrictive... Upgrading to GT40/GT40P heads are the way to go, 0.500 valve lift is near maximum a GT40/P head will flow, so, install the valvesprings, Retainers, Keepers neveded for the Cam you choose. That is a MUST. I included a (board of shame) pic of a customer’s 302, that he'd built his motor with an E-303 Cam, running stock GT40P heads (and Springs, retainers) off an explorer, to show how crucial it is to run correct valvetrain parts, made for a specific Cam.
GT40/P heads will Coilbind under the the lift of a STOCK 5.0 H.O. Cam, and a claytest shouldbe performed with any new Cam to verify you have 0.080 Intake, 0.125 clearance Exhaust to Piston to valve clearance (minimum) at any time, duration is the largest component affecting this, lift is also a contributor. A clay test is a simple checker for this,
Simple test, degreeing the Cam In is also important, for that you’ll want a double roller timing set, with a (9) position crank gear to advance/retard Cam timing. A degree wheel/kit is 60$ on Summit, will have all you need. If the shop assembles it, that’s it!
You’ll also want to go with the Explorer’s lower intake, and upper. If you can find a tubular GT40 upper/lower Intake, or a standard Explorer lower (ported is much, much better) with a cobra upper it’s worth some worthwhile ponies.
Upgrading the GT40 heads to scr ew in studs is also a good idea, machining costs are not expensive. 3/8” ARP Studs make setup easier &more resilience versus to stock pedestal mount Rockers. It’s not necessity, but worth it
The 87’s ran Forged Piston’s with reliefs, weak spot is the 5/16” rod bolts, fine for your build- just shoot for a broad powercurve. You want power just off Idle, it to hit hard by 2,000, and a limiter around 6,000 RPM’s for longevity, or the shop could install good 3/8” rods, run studs in your Main bearing caps.
Both Cams listed are similar, I’m basing parts on the Cams you’re seeking. They’re both single pattern (simply means the Cam same has the Sam lift & duration for Intake/Exhaust). Good but not as good as it could be. Full roller rockers (Stud;fmh) are.
Look at a Trickflow stage 1 Cam, Dyno results on that above combo is +15HP over an E-303 & you’ll have better throttle response at low RPM’s, wider powerband while keeping the motor’s RPM’s out of the danger zone.
Yes, all Cams listed will have a Lopey Idle.
Should do a MAF conversion from (SD) or Speed Density, run 24lb injectors. (50$ harness upgrade, LMR). Run a 70mm or 75mm T.Body, good cool air intake. MAF, L.T. Headers, aftermarket Cat’s on eithermnpn H or X pipe, depending on sound & goals. Cat’hs won’t hurt your performance go any real degree,
Once I know your budget, and your goals, I’ll be happy to spec out some suggestions to get you close to expectations without devastating your budget. The nickel dime items are what makes most overshoot budgets, I try to tally it all in for folks.
The last weak point on a 302 is if you plan on going past 450HP (Crank HP/Gross)), which it doesn’t sound like you’re interested in. The blocks are vulnerable to cracking/braking above that.
I’ll be able to give you some figures & part #’s if you provide the information requested. Remember. Your clutch (if a 5 speed needs a clutch to handle the increased power levels).
Not a bad idea to have someone go through the Transmission and replace worn/broken parts.
As I’d listed above, you should be planting around 275-300RWHP, keep in mind you want to build the car- as a whole- like improving brakes, Chassis stiffening, suspension, Tires (all over time, or anything that needs immediate attention). I’d not listed everything, only the larger priced items.
Remember the best bang for the buck- rear end gears.
LMR sells FRPP Gears, (Ford Racing) the install kit, rear axle seals & bearings, adding 4.10’s to your 2.73, or 3.27 stock equipped gears will help you in a major way, and it’ll feel like a totally different car, much quicker.
Heather 4.10’s vs.3.73’s is mileage concerns with lots of highway use, (or not concerned ). it’ll rev 1,000RPM’s higher at 80MPH with 4.10’s vs stock in a 5 speed, it’s well worth it)!
. Cost of parts & install by a shop that exclusively does transaxle work & a good reputation is your best bet there.
Cost is around 750$ for all parts I’d listed, along with the ships install, do it right in the car. Speedo will be off a bit, Gears are made to correct this, color coded, and are easy to install yourself.
Happy Thanksgiving to you & all else who peeks in, I’ll look for your response to narrow this down.
Good luck!
-John

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