Don Terrill’s Speed-Talk

I recently bought a low milage 1974 454 2 bolt main truck motor and have a few questions. I’ve checked the bores and crank and everything is usable in the std condition so I was thinking about a piston/rod upgrade and putting a good set of aftermarket heads on it to drop into my 69 Chevelle for a cheapo N/A street strip motor. I’ve with my ex-father in law about it he told me it’ll defiantly require a rod bolt upgrade which involves resizing the rods so I got to looking around and found a set of eagle sir6135p 5140 I beam rods with 7/16” arp cap screws for $169 for the set so I bought those. My question is if I were to use the eagle rods with a set of std bore Hypereutectic dome pistons to bump up from the 8.25:1 to 9.5:1 would it require rebalancing the crankshaft? I’m only looking to turn it 6500-7000 at most and I can match weight everything myself.

I'd suggest spending a few extra bucks and doing it right. Have it bored .030 and use forged pistons and get it balanced. A set of Icon or Wiseco pistons isn't to exspensive. The Hyper pistons use a tighter bore clearance which you won't have since it has stock worn cylinders.

If you want to be cheap then just use the stock pistons and rods untouched.

Brian

You might want to ck this out
http://www.chevelles.com/forums/13-perf ... build.html

Save yourself the work of trying to weight match your parts. Unless your machinist knows your work he's going to re do it anyway.

I'm in a drop-top Chevy with the roof wide open
My partners looking at me to see if my eyes open
Cause I've been dranking and I've been smoking
Flying down 285 but I'm focused
454 SS, I race Porsches


sorry, i couldnt resist.

You will want to look at the whole build plan first before selecting pistons.
Save yourself doing things twice and spending more money in the end.
On the 454 BBC the cheap (low cost) pistons ( (TRW speed pro) hyper and forged) tend to have shallow
valve reliefs. So VTP clearance often ends up being too small with a healthy cam ( overlap)
Some of the pistons limit how deep(er) you can cut the reliefs too.
Thus making the slightly more expensive better pistons ( that have deeper reliefs) a better lower cost net deal. If you change the rods and or the pistons you will want to re-balance the crank.
So.....
Again be aware that many of the 454 pistons lack deep enough valve reliefs...
A notorious pesky BBC piston issue. The Icons and the Wiesco's will likely have the deeper relieifs.
Avoiding this from the get go allows you to avoid having to dummy down the camshaft to make it fit. (less allowable valve overlap due to lack of VTP clearance.) The result is more power for slightly more money spent in the right area cause you can cam it properly.
I'd also CC the heads FIRST to verify chamber volume and then select the right piston dome volune to get a 10:1cr 10.50:1cr for 92 octane gas. Getting the compression right instead of just ball park "9.5"
is money and time well spent to get a great result.
The BBC heads are rarely what you think they are. "Measure twice, cut once".

I always recomend you measure the VTP clearance (and the piston deck clearance too). of the stock motor assembly BEFORE you take it all apart. You can also PRE inspect for the things like a slightly tweeked rod or bad lifter bore etc.

Also be aware that when bolting on aftermarket cylinder heads on a BBC the piston dome may hit the chamber at TDC,, May require minor dome clearance grinding. It is something you have to check. Many of the ("cheap") more affordable 454 pistons dome is made for the OEM factory OC or CC heads no the aftermarket heads chamber nor the OEM oval port heads too.

vortecpro wrote: ↑Mon Feb 12, 2018 11:20 pm You might want to ck this out
http://www.chevelles.com/forums/13-perf ... build.html

Listen to Vortec. He flat out KNOWS what NEEDS to be done, and what should be done. Very open and honest person. Use him for a cam too!!!!!!

I would go the .030 over forge route with the rods you bought, and get it balanced for piece of mind more than anything. You can make GREAT power with OEM stuff, just need the right attention to details.

Good luck

Thumb rods, forged flat-tops and an old pair of -206 large ovals and a good valve job and an old UDHarold cam along with a 4-tube, long tube, set of 1.75" to 1.875" dia. headers and you should be good to go.

Oh, install the thin .020" thick steel shim head gaskets to gain a skosh of CR. Also an old Weiand 8005 or Performer Q-Jet intake too.

Nothing fancy at all here, but it just works, imho. And VortecPro knows his stuff!!

pdq67

It's been almost 15 years, but we did a nice little street rat a while ago, and not a bank breaker, but made decent numbers and behaved nicely

462 inch Rat, 10.2:1, rebuilt rods, but today I'd go aftermarket, Comp Magnum, I think it was 288 advertised, mid 240's @ .050, but nothing special, single pattern off the shelf solid roller, only think we had that was real nice was a real nice stud girdle up top and stainless rockers, Team G intake, 850 double pumper and a set of whatever Brodix sold back then that was in the lower 300's for intake volume. Smaller heads, but not their smallest (sorry, it's been a LONG time), I seem to remember though they had three street offerings back then. Headers were pretty big, 2 or 2 1/8

I also agree with a previous post to check domes carefully, and I'll add, if buying heads, try to tighten up the chamber so you can run less dome, those big chambers use quite a bit of dome to get some compression

That engine was pretty darn mild, sounded great and made 602 hp at 6100 RPM on Kel's dyno in Las Vegas, not killer numbers nowadays, but behaved well in traffic and hauled the mail with regular parts ordered from Summit.

vortecpro wrote: ↑Mon Feb 12, 2018 11:20 pm You might want to ck this out
http://www.chevelles.com/forums/13-perf ... build.html

Hey Vortec, i read the complete post of your build on the chevelle forum. It is phenomenal!
Really impressive. Let us know how it runs in your chevelle.