Upgrades / engine rebuild thoughts

[Arquemann]

So,
I'm thinking (and overthinking) at the lopo 302 rebuild looming in the near future. Next winter to be more exact. (this all under the premise that my block is worth rebuilding)
Basic plan is basic, .30" overbore, H273CP pistons, new bearings and rings, balanced. What else I might need I don't know. Line bore, valve job, deck surfacing. If shit goes south too much, it'll be cheaper to buy another motor.
Currently the engine is stock, except for a Weiand Street warrior intake, Holley 4bbl and HEI ignition. Also the exh. manifolds are staying, for now. I know the exhaust is shit.

My budget being not much, I haven't put much thought into upgrades, except for one, or maybe another one:
- Cam
OR
- Heads

Heads are a simple-ish upgrade I guess, I don't think I'll be splurging for alu heads, just some better iron heads if any come up. From what I've read the E5 heads I have aren't exactly spectacular and as long as I'm not replacing them with heads with bigger combustion chambers or E6SEs, it ought to be an improvement.
I just don't quite like the idea of changing heads due to the many things that need to be addressed along. Finding worthwhile heads to use, CC's, 351/302 head bolts, valve geometry, pushrods, rocker adjustments, PtV clearances.

Whereas I quite like the idea of changing the cam. I have a roller block, so the benefit of a roller cam is a drop-in solution. That would also mean swapping to the HO firing order, which is somehow better I've understood? Free up a little horsepower from the roller setup, along whatever would come from the cam itself. Also not having to do a critical cam break-in sounds great. For budget purposes I wouldn't mind picking a stock replacement cam from a late model 351 or 302, like an explorer or F150 or whatever cam would have the meatiest low-end torque, small budget, aftermarket or not. I have zero interest in high RPM power, I want good driveability and TERK.


Tell me I'm doing the right choices or tell me that I'm an idiot and doing everything wrong, atleast tell me what I should do.
I want an efficient setup, good driveability, torque down low and all done by 4500rpm, which is enough for the AOD (and me).

[friskyfrankie]

I guess the big question, even before thinking about parts is: Do you have a capable person to rebuild the entire engine. Not many people doing it and even less doing it well. Then consider what parts you wish and do you have the funds to buy them. Of course, once someone digs into the engine, they may find more things that need repair/replacing that no one even knew about. Always allow MUCH more money than you expected.

[Arquemann]

I guess the big question, even before thinking about parts is: Do you have a capable person to rebuild the entire engine. Not many people doing it and even less doing it well. Then consider what parts you wish and do you have the funds to buy them. Of course, once someone digs into the engine, they may find more things that need repair/replacing that no one even knew about. Always allow MUCH more money than you expected.

I'm doing it and no, I haven't rebuilt engines before. But I have my dad and my engineer's meticulous mindset aswell being quite particular on doing things to a high standard.
Once the engine is pulled, it'll be disassembled completely. If the major parts look fine by eye, they'll go to a known good machine shop for crack checks and so on. I'm on a budget, but I'm not that dumb to slap it together with whatever. Maybe I have a cracked block, maybe I have a bent rod and scored crank. I'm not making moves before I know exactly what to do.

[friskyfrankie]

I'm doing it and no, I haven't rebuilt engines before. But I have my dad and my engineer's meticulous mindset aswell being quite particular on doing things to a high standard.
Once the engine is pulled, it'll be disassembled completely. If the major parts look fine by eye, they'll go to a known good machine shop for crack checks and so on. I'm on a budget, but I'm not that dumb to slap it together with whatever. Maybe I have a cracked block, maybe I have a bent rod and scored crank. I'm not making moves before I know exactly what to do.

Didn't realize you were doing the work yourself (mostly, anyway). Being meticulous and having your Dad to help should be a nice project. In that case, go for it! Just be sure to budget much more than you expect and be prepared to spend even more than that. If you are fortunate and don't have to over spend, then great!

[Tiggie]

Stock heads absolutely suck. They kill it. I regret using stock heads in my 68 but don't want to blow it all apart since it's pretty now. I repeat, don't use the stock heads. GT40 (not p) if you need something cheap but by the time you go through them, you might as well get new aluminum ones. P's need those weird headers but I think they kinda work with stock manifolds.

If I were building a 302 and had the coin, I would get blueprint heads and a stock HO stick. 350 horses and it sounds nearly stock. Don't skip the headers. Your intake will be okay. The AOD will hold it if you don't drive like a maniac.

https://www.summitracing.com/parts/MLL-HP9009

[sly]

+1 if you can afford it, get an HO (351 firing order) style cam. It will cause less stress on the rear main bearing and not cost much at all. If you want to port and polish the heads to save money, there's a LOT of meat that can be removed from the stock heads to widen the ports, but the chamber can't really be modified much IIRC. Obviously, some aftermarket heads would be better, or if you can get gt40 heads from mid 90s Explorers (96-97.5) - doubtful considering your location, but it's something to look out for as those heads flow really well. Since it's an 85, it should be roller compatible (will need the lifter retainer plate and two holes drilled and tapped in the block for the bolts to retain said plate along with the roller lifters and dog bones) so you could use a roller cam, but it should be flat tappet currently, so a flat tappet 351 firing order cam with moderate specs will work nicely. The rest you seem to have pretty well sorted.

[gadget73]

do you have a roller compatible block? The tell is under the intake, there will be 2 raised bosses in the center of the lifter galley that are or could be drilled and tapped for the lifter retainer spider. If not, frankly I wouldn't waste my money. Find a roller motor and rebuild that. It gets you away from all the nonsense with flat tappet cams and modern oils. I realize where you are makes that less practical but basically every car from 1986 onward 302 had one or was at least a compatible block. Some of the trucks didn't get roller cams until the early 90s but the blocks had the provisions for the hardware. The stock hardware shouldn't be too hard to get or cost stupid money either. Its plenty fine for any sort of reasonable power level.

stock SBF heads are terrible, the only as-cast ones worth bothering with are the GT40 or GT40P, and the P heads need special headers that are hard to get now. They can be ported and have potential if you do that but unless you're going to do it yourself, you can probably just buy something much better for the money you will spend on having someone make a set of stock heads not suck.

[Arquemann]

Yes I do have a roller block, the bosses are already threaded.

How much of a difference is there between the stock lopo flat tappet cam and a later HO cam? I thought an explorer cam or such would be a better fit, but it seems they are just a worse HO cam. I'd like to believe I could snag a used Mustang HO cam pretty cheap. Or are there other better choices for cheap?

New alu heads are foooooking expensive, cheapest are like 1500€ a pair for E-street heads and most other stuff has huge intake CCs. I don't know much about cyl head specs but I understand that overly big intake ports don't play nice with low rpm torque. GT40s will be tough to find, there's plenty of exploders in Finland, but I've never seen a 5.0 for sale, all 4 liters.
I have a friend that might take a jab at my E5 heads with a die grinder for some beers. In case I come up with nothing in the heads department.

Also got a little bitty surprise in the RR thread.

[sick88tbird]

IF you’re on a budget and plan on having the heads reconditioned anyway, I would have them milled .030” for a little bump in compression and get a 5-angle valve job with a little bowl-blending to match up with the valve-job and a 30* back-cut on the intake valves. Even with stock valve size, that should gain 15-20cfm.

If you’re using a low-lift cam that doesn’t have real aggressive lobes(i.e. any stock cam) you can have the valves and seats cut on at 30* instead of the traditional 45*. You’d still want at least 3 angles cut under the seat to transition into the bowls. 30* seats may be a better option for you as it presents more area for airflow under .300” lift. Basically, it’s like having larger valves. No matter what you do, install stiffer valvesprings, stock are junk.

If your budget is really keeping you limited to stock type cams, the LOPO roller cam is your absolute best bet for off-idle torque. With a 30* valve job, and your intake and carb, it should make great torque and pull strong to 3800-4000rpm. If you’re leaving the heads alone, then I’d go with a bigger cam to help crutch the heads. An HO cam will peak at 4200-4700rpm typically, but if your limiting RPM to 4500, then having your peak power there or a little after is less than ideal.

[gadget73]

The Explorer cam is like a stock cam on steroids. Very similar overall feel except its got more power, and its completely done by 4500 rpm. The stock cam is done around the same point though. I ran one for a good while, and it was OK but what I have now works a lot better IMO.

In a stock engine, the HO is kind of dead under about 2500 rpm but will pull to 5500 or so. Unless you change the rear gearing or the torque converter, quite honestly the HO kind of sucks in a heavy car with an auto and a tight converter. My Mark VII is basically the same weight as a Vic / Grand Marq and with the AOD and 3.27 gears its not exactly a rocketship off the line. The one I wrecked got a lot better with the upgraded lower intake even with stock heads though, so with improved airflow I would expect improvements over how a bog stock EFI HO performs. Still wouldn't suspect its ever going to be a low rpm torque monster though. Consider they were intended for Mustangs which are some 800 lbs lighter. Stick a 3.55 or 3.73 gear set in there and/or a higher stall converter and it would be a different story.

The E5 are similar to stock HO E7 heads so most of the porting advice should apply. At a minimum if the air injection lumps in the exhaust got ground down and the intake side was gasket matched it will make it suck a lot less.

[Arquemann]

So the HO cam is pretty clearly a poor choice in my situation. The truck/van/suv F4TE cam would probably be the best stock cam for me, only if I could find one cheap.
I guess I could maybe focus more on better heads, but it'd be kind of a shame to leave the lopo flat tappet in there.
Sucks that almost all stock replacement cams are out of stock and I can't see the prices. Some hopped up Melling cams are available and they're 300+ euros.

[gadget73]

used roller cams are a viable option, unless something dumb has happened they really don't wear.

[Grand1]

For a cheap upgrade, I was wondering if anyone has put Flowtec heads,(?)they start at $350 a piece. In the realm of aluminum heads that's more than decent. The specs look pretty decent.

[Arquemann]

For a cheap upgrade, I was wondering if anyone has put Flowtec heads,(?)they start at $350 a piece. In the realm of aluminum heads that's more than decent. The specs look pretty decent.

The cheaper ones are $459 a pop with guts in them, not bad I guess, but for ~$900 they're still on your side of the pond. They do look pretty though.

[Lutrova]

What's the differential between those Flowtecs and the cost to refurbish a pair of GT40s?