considering a Paxton sc since I found a few really cheap. if I swap to low comp cast pistons would they hold up. mustangs hold up with them on stock motors so would the nail be any different. it would be low boost 5-7 psi max. car will def have a tbi unit on it.
As long as you don't detonate it, yes. That means strict control over fuel mixture and ignition timing. Much easier to do with microprocessor control.:grin:
well I want to go with fitech tbi so it should be ok with that. this may never come out but its a ponder im weighing. been working on the car some again.
well not have a carb in any way. I don't have a carb at this time and really im not a fan of them. I def want the car to be efi either way. I may just stay na and just cam it up. but I figured if I can find a used sc for a few hundred why not.
Understood! My thoughts were to NOT spend a penny on pistons that 'might' survive, assuming no mishaps. The engines put together 'getting away' with cast pistons and superchargers were meant to be expendable cheap fun. Please don't do this with a Nailhead. Better ways to get by might be, 1. Buick 455 or Pontiac rod and forged 454 piston. 2. Find some other way to save the tiny difference between a 'low cost cast piston' and a forged one. I was assuming that many hot rodders always seem to have carbs around, and that they are fairly brainless to tune for a combo such as proposed.
What is your current compression ratio? I do not know about the nailhead but with the Buick 350 the stock cast pistons seem to work fine with boost. I was running stock pistons in a Buick 350 without a problem until we went to higher boost and then had head gasket issues. Still no issues with the stock pistons. As people are saying it would be a shame to loose a good Nailhead engine over some low cost pistons. The mustang 302 engine have forged pistons if I am thinking of the same era of fox body engines? Like people are saying it is all in the tune whether stuff will break or not.... My $1000 Diamond pistons in my good engine would still be damaged by a bad tune, they just may put up with more abuse before they fail.
If some old forged Nail pistons were lying around, some dome could be trimmed away. Lots of the 5.0's did have forged pistons.
My dad ran a 100 shot of nitrous for years on his 425 Nailhead with cast pistons. He had his full weight '64 Riviera running 12.60's and put hundreds of 1/4 mile passes on it. It was triggered by the carb linkage at full throttle. I can't imagine the supercharger being any worse on it. Just make sure it gets enough good fuel and keep the timing in check. Ken
Google is your friend. Look at all the dimensions and you'll start to see some solutions to your problem.
Perhaps I can help, first off what size bore does the engine have now? Is it a 401 or a 425? And would you just want to run a stock stroke or would you not mind stroking the crank a bit? If you're working with a 401, there are a lot of cheap nascar take out AND new pistons that are close to the 401's bore size priced really CHEAP! If you don't mind a little extra work assembling the engine I can probably find some sweet parts that would work great in an application like that. Derek
There's a few BBC rods that can work, too. All of these options 'might' be less costly than starting with a cast piston.
401 and I wouldn't care really stroked or not. na stroker actually gets me in the area I want in power too. id like to make 400 rwhp out of the engine. I prob wouldn't complain if it was in the mid 300s.
You have forged rods and a forged crank already in the Nailhead. Forged pistons are all that is needed for a stout rotating assembly for supercharging. Tom (Telriv) on this site is working with a manufacturer making custom forged pistons. He would be able to get a piston custom tailored for supercharging reasonably. Also, Venola was making a forged Nailhead pistons in a few compression ratios a few years ago at a decent price. Cheryl Sent from my iPhone using Tapatalk
On a nailhead,,, you have forged steel rods and a forged steel crank from the factory.... :Brow: plenty strong.... the weak point is the cast factory pistons... plus ... high mileage.... I would go with forged pistons for a bullet proof short block....
I used a $150 set of NOS 454 pistons with an extra set of b455 rods and slightly massaged the dome and simply left the extra side clearance, rebushed rod for pin size. Piston speed only changes 1.8% (?) with that longer combo. Another used a 6.535 BBC rod with a 454 piston, crank needed grinding anyways, I think I ground the rod sides, too. The Pontiac rod also uses the same bearing, and would need the small end honed. RM does it this way too. Bore sizes cover both Nail's, with several domes to work with. There's enough material in the right places to trim most .580 dome slugs to fit the chamber, the short domes are often solid. 25 grams of bobweight is appx 1%, so weight matching would be the biggest concern (unless really light, lol). The machining for me is only time. The easiest way is to cough up more dough for a nail specific slug and sleep at night. Reduce your budget elsewhere if it bothers you.
this is all in my head right now anyhow so who knows what will happen when I get down to it. I may just be like screw it throw a cam in it and go. the motor is low mile with a pretty fresh rebuild before I got it. so in reality I don't need to take it apart but I would for another 100 hp. I have the heads off it but after I saw how good it looked inside I was like that was pointless. arp rod bolts and so forth. I may just clean up match the head and intake cam it and go. id like it to pull 12s if I wanted too so that's my goal. has a 200-4r behind it with 342 gears. full weight car minus say the clutch fan and aluminum radiator.
New forged Nailhead pistons are around $850 with rings. Tough to find older ones, but both TRW and Ross offered them in the stock compression ratio..... 10.25:1 'advertised' but actually about 9.75:1 in a production engine. Use a thick composition head gasket and compression drops even more. It's a big piston. I've seen cracked/collapsed domes on the stock cast pistons from detonation! Take a look at the Chev 427 and 454 pistons at Summit Racing. They have pop-up domes in various sizes. The Nailhead has about a 46cc dome. These sound like what F85 was talking about. Machining can get real expensive if you have to pay someone to do it. Cool to know someone has been able to make these work. It's tough to get 12's from a 401. A bigger cam likes higher compression. Most stockers run mid 14's so it takes some planning to get into the 12's. My blue 66 runs 13.4. I built the engine when I was 17 and didn't know any better.... I put in a big Isky cam and had to machine valve reliefs into the pistons for clearance. That, and the thick head gasket probably dropped the compression down to 9:1. I did some DIY head porting, added headers and rejetted a '66 Q-jet and it runs better than it should! Bet I could get it into the 12's with the right cam and compression ratio.
well to hit high 12s I need 350 rwhp so im seeing some cars making that with the heads intake done and right cam. so I may go that route. plus I can save some bones by staying around that with the efi unit. going to much higher hp and boost will ad a few hundred. im also going for a set of roller rockers. I would like to get my weight down some but keep the car comfortable as possible.
