Thread: wanted 500hp from 454
Threaded View
-
10-08-2006 11:31 AM #1
wanted 500hp from 454
Hi guys - I'm new here!
My pride & joy is a 1968 Iso Grifo 7-Liter, which for those who are unfamiliar, is an Italian 2-seat GT, using good old US V8 muscle. Most of the 412 built were 327-powered, but there were also some 350 small-blocks, and later on, Ford 351C. Included were 90 built with Chevy 427 or 454. They are great-looking cars, and can hold their own with contemporary Ferraris, Masers and Lambos.
I have just done a major rebuild on the engine, and generally, I am really happy with it. It gave 463hp at 5400, and 522ft lb at 3800 on the dyno.
The rotating assembly is all good stuff - forged crank, 4-bolts, Manley H-beam rods, forged 9.8:1 slugs, steel flywheel, Fluidampr - so it can take plenty of hp.
Heads are Edelbrock Performer RPM, fitted with Comp Cams beehive springs and titanium retainers (to try and beat valve-float with hydraulic roller). Carb is a Holley 750 double-pumper massaged by Chuck Nuytten of Dallas specifically for this engine, and am told it will flow up to 890cfm. Exhaust is custom stainless long 4-into-1 headers with twin 3" pipes and mufflers (sounds awesome!).
We can get 97 octane over here in England, but over 7 bucks a gallon - ouch!
Gearing is very high - 2.88 rear end with Super T-10 4-speed with a 2.88 1st gear. This car needs to top 170mph (in Germany, of course!)
However, I am very tempted to try a Tremec TKO600 5-speed with the 0.82 5th ratio and a 3.31 axle. I reckon the gearing would be about perfect then - decent acceleration and high top end.
At the moment I have a Lunati hydraulic roller, fairly mild with 218/226 @ .050", 112 deg lobe centre, and .534/.544" lift.
I feel the engine isn't as eager above 4000rpm as I would like. I would like it to feel as though it wants to race up to 5000+ rpm. So, I would like to raise the torque peak to about 4100 and hp to say, 5800.
My question (finally!) is: would a hydraulic roller of 230/236 deg @ .050", with same LC and .547/.547 lift do the trick?
I would be pleased to get nearer to 500hp, and realise the torque would probably drop to more like 500ft?
I'd be interested to hear any views!!
John's ride to the cemetery, his beloved Billings OK bus, The Baby Elephant!! Traveling in style!! As his service was starting I couldn't figure out what the music was, heavy on a flute in a jaunty...
John Norton aka johnboy