Ive watched and enjoyed your forum for a while, this is my first post.
Im looking for opinion for a motor im currently building:
4V 351 +30, solid cam 575/600 lift, 247/257 @50, 107 lobe sep, shot peened rods with ARP bolts, 4MAB crank, 10.5: 1 comp with 4V closed chamber heads on PULP.
Useage will be street/strip, 6500 rpm limit, looking for 480-500HP.
My dilema is 3 fold:
1) What piston will suit my application without going over board?
2) What is the best inlet manifold to suit? ive got a 4V torker at the moment, will it do? or do i need to go bigger?
3) should i use inlet tounges on these heads?
My ports are actually ported !, but i have 4:88 gears which helps the 4v's down low.
I have not tried tounges myself, but i hear they are good for windspeed.
My combo is similar, except i have a 850 dp, and a much bigger cam.
Thanks for your help,
what are peoples opinion of ACL pistons? Both the duralite and Racer series.
Forged pistons seem a bit over the top for an engine that will be in a weekend street car? or will the HP figure im looking at make it manditory,
Your compression is really borderline for pistons that aren't forged. Most non-forged pistons state a safe compresion ratio as 10:1 but you can get away with 10.5:1. I am sure ACL states this on their website too.
not an expert but id go the inlet tounges for the low down torque and since its "only" going to be revved to 6500rpm. didnt the xy gtho's rev to 7500rpm down conrod?
also heard the x-cellerator is an excellent manifold, everything ive read to do with it has given it a thumbs up, and would be very suitable for the 6500rpm limit
the torker obviously would work but if u can find an x-cellerator at the right price i would go for it. either way u go port matching would help.
re-reading ur post i noticed your power goal which is very realistic indeed.
The torker will be fine for what you want to do. I personally chose the TFC because of it's top end capabilities.
I have installed port toungues, even NASCAR motors that revved to 8000rpm still had their ports filled in. It greatly increases air velocity.
I found that the ACL race series piston to be quite good, but as said earlier there are forgies out there which aren't bad. I would go for a 6" 302 rod on your 351 crank and use a SRP forged alloy piston, they go for approx $800-900 and will give you 357ci at 30 thou with 10.3:1 compression with a 64cc 4V closed chamber head. big HP potential.
You have some good pieces there? (carb etc.) With that crank, maybe a set of 6" forged rods ($600 or so) and maybe consider solid roller, you can aim for 500-550hp.
Best of luck mate, cant wait to see it happen. Mine is almost there and i just cannot wait to hear her for the first time...
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