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small block performance
Wazz-up guys,
I'm new to the club,probably asking a small block question thats been asked more than once or twice. I have a johnspeed w/ a 351w(stage II performance,330 HP,I question that)the engine is probably a mid 70's,it has the smog passages on the rear,blocked off. The car is pretty quick,but I want a little more(don't we all). I try to do things right the first time rather than try,try and try again. The engine seems to peterout/flatline,quit pulling @5300 rpm. I'm running the msd pro billet dist(w/med advance springs,max advance setting 28 if I remember correcty) I'm thinking looking @ the Edelbrock raised heads with 2.02 intake valves and a roller cam. Engine already runs a performer intake and a Holley 4100. I think the bottom end is stock,I haven't had to perform any surgery yet,or should I save my pennies and think of something more like the Ford Motorsport 392 stroker? Or am I eventualy going to want an alum body,titanium frame,427 SOHC/CAMMER motor(not that there's anything wrong with that!) Should I wait untill something breaks and follow the racing rule,build it bigger,better,faster and stronger. Dose the road to excess lead to the house of wisdom?? |
Ted,
You might contact Bill Emerson at Emerson Motorsports about your set up. He is on the club and I know he has used about every stage of the Idelbrock kits for 351s and the people that I have talked to really like them. I believe one guy told me he called edilbrock and they told him with the set-up he used he should be getting around 400-426 horse and the car runs great. Ron |
You aren't going to want to buy heads, unless you know what pistons you have, otherwise compression ratio is unknown. I would start by giving your motor a few more degrees of ignition timing, 28 is good for a really hot smallblock with very efficient combustion chambers, 34 might be more to your motor's liking.
You could get what you want buying ONLY: heads, pistons, cam, lifters, rockers, (and gaskets, oil pump, timing chain while you're in there) But by then, you might as well spring the extra few bucks for a stroker crank and some block machining, cause you are allready almost completely redoing the whole motor. If you don't want to spend so much money, new cam and lifters( and valvesprings) will make it a different motor, maybe not much faster, but different. |
Thanks for the tips,Ron61 and Mr.Fixit.
Mr.Fixit,when you say additional timing advance,are we talking base or total advance?? I think I have the smallest advance spacer(the most I can get with msd's setup). Any advice about a fluid balancer(I don't noice any vibbration problems). Any benifits? I think the heads,cam,lifter roller rocker set would run about $2000.00,give or take. With the oil pump suggestion,next question. Will the 289/302 slampan,from Jeg's work? I dented the oil pan first time out at the track.It dosen't leak yet! |
Total advance should be about 34 degrees for a mild small block.
Fluidampner's are OK, I have one in my house as a doorstop right now. Must remove outer fluid filled ring for balancing the rotating assembly. Don't buy heads without getting pistons that will work with them. I don't know about the Jeg's slampan, I don't buy mailorder as I live in socal where speedshops are still in business. |
Thanks for all the advice MrFixit!
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Terrible Ted 13,
Is your intake a Performer or Performer RPM? If it is a Performer, I suspect that it is the reason your are flat lining at 5,300. Most Performer intakes just plain give out at between 5K and 5,500. If you only have a Performer, I would suggest that you add a new intake to your list of things to buy. It will remain to be the bottle neck in your engine's performance. Bud |
George Snyder,
I do have the Perfomer RPM intake,sorry for the inaccurate info. Thanks for the help. I need to get the dial advance timing light. |
Ted,
I second the idea of checking your total advance. We can actually handle a couple of extra degrees of advance here at altitude. I run my 393 at 36 deg total with alu heads - iron should be happy with 34 total. Perhaps you could consider a bit of port work on the iron heads before you invest in new aluminum heads. Also your Holley is probably a bit too big for the 351 at altitude. I reduced my 750cfm to a 650cfm and picked up a noticable increase in mid range (3000 to 5000 rpm) response. An hour on a local dyno with a skilled tuner would probably wake up your 351 and give you a good base line to start from. Give Walt Hane a call at EPS in Evergreen. |
I would swap the intake before adding roller rockers. They just don't give you that much horse for the amount of money you spend. Also what Fixit said about the heads. They need to be matched to the bottom end and the RMP you plan to operate. Big port/polish with huge runners will kill the velocity at low compression and/or low RPM.
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