You had expressed some interest in knowing a few more particulars of the Hotrod article i was quoting earlier this week in another thread.The whole point of the article was to make a 350 with around 300 hp.that could propel a 3,300 pound car to 13 sec. e.t.s'.with very little money.The engine was equipped with typical 70s' heads 194-150,76 cc. (882's) had a stock bore, and new cam that measured 0.442/0.465 inch lift and 214/224 deg.of dur.at 0.050.They used a 305 h.o. stock aluminum intake and did change the valve springs and did a 3 angle valve job on the heads before putting it all back together.They even milled the heads down to 74 cc to try and improve the compression.After some tuning on the dyno ,they ended up with 283 hpand 343lb-ft of torque.They then put on the tpi heads that had come off of a 90'trans-am 5.7litre (sorry,they weren't 94s'.The ones i used were off a 94'tbi truck).The next pull gave them 299.3 hp.,Over 16 horse from just the heads.I thought this was a noteworthy gain.Incidentally,they then went to vortec heads with a performer intake and exteme energy comp cam and made like 375 hp,But they spent alot more to get that kind of power.I was very short of cash when i built my engine last summer and used this as kind of a template for my mill.So far it's been very dependable and works pretty well for what i have in it.Anyway,thats why i thought Xenodrgn might be interested in the tpi head tip.i'll keep the facts straighter next time.See ya.

 

Interesting...

IIRC, the original question I had was what they changed from, when they put on the L98 heads and picked up however much HP. It's hard to compare 2 things when you don't know what one of them is.

Those results are actually a little less of a difference than one often sees making a swap like that. Almost sounds like the smoggers had a little porting and the L98s didn't. Did they say what if anything had been done to the L98 heads?

It would be worth knowing what would happen if you took a pair of 70s smoggers and a pair of double-humps and a pair of 416s and a pair of L98 heads and maybe some Vortecs, and did some reasonable amount of port work to them all, say, gave them 4 hours in a machine shop (kind of typical for a street port job), but left them in typical budget street build condition (no expensive valves or any stuff like that); and then did the back-to-back dyno thing on a generic motor with some typical street cam like that one in your test. That would take alot of the variables out of the mix, so you could easily compare apples to apples so to speak. Maybe we can talk some one of the mags into doing something like that.

Thanks for the clarification.

 

Sounds like a interesting Project.
I just happen to have that Generic motor with that cam.
The Generic car, and access to a dyno.
got the Vortecs, the 920's (70's smoggers) and the ported 416's
all I need is the tpi castings and the time and $ to do it.

Maybe one of those Mags needs a good "Backyard Build Up"
or "Junkyard Dog" type story and would be willing to put up the bucks to pull it off.

It's always the low buck buildup stories where some guy scrimped and scrounged and modified to throw something together with what ever was available for low$$$ that makes me buy a mag at the newsstand.

 

The article said that nothing had been done to the tpi heads before they were put on and run.They had 40,000 miles on them when some guy discarded them for a set of aluminum corvette heads.I would think the difference would have been greater if the heads would have had the work that the smoggers did.They didn't mention any porting done on the 882's by the way.